**Triangular numbers: a(n) = C(n+1,2) = n(n+1)/2 = 0+1+2+...+n.**

*0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210*

Index of A-numbers in seqfan: by ascending order
by month
by frequency
by keyword

*60 seqfan posts*

*Mon Jun 25 12:35:01 CEST 2012* [seqfan] Re: OEIS page header image

*Sat Aug 6 20:13:07 CEST 2011* [seqfan] Non-Attacking Triangular Board Rooks, guess the recurrence

*Wed Jun 29 23:02:15 CEST 2011* [seqfan] Re: On ethics

*Wed Mar 2 17:16:33 CET 2011* [seqfan] a(a(n)) is a triangular number

*Tue Jan 25 10:23:09 CET 2011* [seqfan] Re: OEISWiki : decomposition into weight * level + jump

*Thu Dec 2 18:16:11 CET 2010* [seqfan] Re: Trotter Math

*Sat Nov 27 04:50:31 CET 2010* [seqfan] Re: OEIS Search changed?

*Sat Nov 27 02:52:33 CET 2010* [seqfan] Re: OEIS Search changed?

*Thu Nov 25 19:50:44 CET 2010* [seqfan] Re: OEIS Search changed?

*Thu Nov 25 17:28:24 CET 2010* [seqfan] Re: OEIS Search changed?

*Thu Nov 25 06:32:46 CET 2010* [seqfan] OEIS Search changed?

*Fri Oct 29 05:35:16 CEST 2010* [seqfan] Implementing first 500 sequences in Java

*Fri Oct 15 08:27:45 CEST 2010* [seqfan] Re: Request for references

*Fri Oct 8 23:01:20 CEST 2010* [seqfan] Re: trouble with A132337 and A132336

*Fri Oct 8 22:58:43 CEST 2010* [seqfan] Re: trouble with A132337 and A132336

*Fri Oct 8 22:45:03 CEST 2010* [seqfan] Re: trouble with A132337 and A132336

*Wed Oct 6 17:26:48 CEST 2010* [seqfan] Request for references

*Mon Sep 27 01:30:55 CEST 2010* [seqfan] Sigma(T(n))=T(m)

*Sun Sep 26 06:48:14 CEST 2010* [seqfan] Re: n-th number whose sum of divisors is a n-gonal number

*Sun Sep 26 05:22:18 CEST 2010* [seqfan] Re: n-th number whose sum of divisors is a n-gonal number

*Sat Sep 25 22:43:13 CEST 2010* [seqfan] n-th number whose sum of divisors is a n-gonal number

*Wed Jul 28 20:25:39 CEST 2010* [seqfan] Re: Numbers n such that the decimal representation of n is contained as substring in that of the n-th pentagonal number.

*Tue Jul 27 12:19:12 CEST 2010* [seqfan] Re: Numbers n such that the decimal representation of n is contained as substring in that of the n-th pentagonal number.

*Tue Jul 27 03:22:34 CEST 2010* [seqfan] Re: Numbers n such that the decimal representation of n is contained as substring in that of the n-th pentagonal number.

*Tue Jul 27 03:12:01 CEST 2010* [seqfan] Re: Numbers n such that the decimal representation of n is contained as substring in that of the n-th pentagonal number.

*Tue Jul 27 02:45:24 CEST 2010* [seqfan] Numbers n such that the decimal representation of n is contained as substring in that of the n-th pentagonal number.

*Tue Jun 15 03:40:11 CEST 2010* [seqfan] Re: Concerns about some recent comments by Jaroslav Krizek

*Fri Jun 4 18:01:20 CEST 2010* [seqfan] Re: 3D version of A000938: 3-in-line inside the nXnXn cube

*Sun May 30 16:41:20 CEST 2010* [seqfan] Re: Concordance to "What's Special About This Number?"

*Sun May 30 16:21:04 CEST 2010* [seqfan] Re: Concordance to "What's Special About This Number?"

*Sun May 30 10:36:19 CEST 2010* [seqfan] Partial sum of Pascal's triangle is a power of 2.

*Tue May 11 13:05:45 CEST 2010* [seqfan] Re: puzzle suitable to make a sequence ?

*Sat May 1 17:30:24 CEST 2010* [seqfan] Re: A possible list of new sequences

*Sat May 1 15:12:55 CEST 2010* [seqfan] Re: A possible list of new sequences

*Sat May 1 13:12:04 CEST 2010* [seqfan] A possible list of new sequences

*Fri Mar 12 13:04:49 CET 2010* [seqfan] Re: editing A000217 Triangular numbers

*Fri Mar 12 11:54:58 CET 2010* [seqfan] Re: editing A000217 Triangular numbers (long message)

*Fri Mar 12 10:09:44 CET 2010* [seqfan] editing A000217 Triangular numbers (long message)

*Sun Mar 7 01:52:50 CET 2010* [seqfan] Re: Sums of two sequences

*Mon Jan 11 08:26:44 CET 2010* [seqfan] FW: Re: Sums of each ten terms of A033308

*Mon Nov 23 01:38:36 CET 2009* [seqfan] Re: Meanwhile, something fringe...

*Sun Oct 18 17:21:22 CEST 2009* [seqfan] Re: Anagrams of triangular numbers

*Sun Oct 18 02:50:01 CEST 2009* [seqfan] Re: Anagrams of triangular numbers

*Sun Oct 18 02:08:12 CEST 2009* [seqfan] Re: Anagrams of triangular numbers

*Fri Sep 25 20:40:38 CEST 2009* [seqfan] Re: Number of ways to write n^2 as the sum of n odd numbers

*Tue Sep 15 23:55:36 CEST 2009* [seqfan] Re: Gen. Functs. A039219

*Mon Aug 24 18:46:51 CEST 2009* [seqfan] Re: Futurevalue considered harmful

*Thu Aug 13 22:36:32 CEST 2009* [seqfan] Re: Rant on Maple code

*Sun Aug 2 05:53:42 CEST 2009* [seqfan] Re: Q: formula in A054556

*Fri Jul 31 16:02:57 CEST 2009* [seqfan] Q: formula in A054556

*Sat Jul 11 18:09:06 CEST 2009* [seqfan] Re: Triplicate

*Wed Jun 3 16:30:51 CEST 2009* [seqfan] Re: possible relation in A005132 Recaman's sequence

*Wed Jun 3 16:19:15 CEST 2009* [seqfan] Re: possible relation in A005132 Recaman's sequence

*Thu May 14 17:29:17 CEST 2009* [seqfan] Re: need help with query

*Thu May 14 16:38:16 CEST 2009* [seqfan] need help with query

*Thu Apr 23 21:29:22 CEST 2009* [seqfan] Re: Offsets for Recurrence Sequences

*Tue Apr 21 23:36:56 CEST 2009* [seqfan] comments about perfect numbers

*Sat Mar 7 11:54:06 CET 2009* [seqfan] Re: Squares in a grid

*Mon Jan 12 11:27:00 CET 2009* [seqfan] Re: Index of linear recurrences

*Tue Jan 6 17:00:06 CET 2009* [seqfan] Re: FYI - conjecture: n=x^2+T_y+F_m

Index of A-numbers in seqfan: by ascending order
by month
by frequency
by keyword

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