# [seqfan] Re: Q: formula in A054556

Joerg Arndt arndt at jjj.de
Sun Aug 2 05:53:42 CEST 2009

```? v=[1, 4, 14, 31, 55, 86, 124, 169, 221, 280, 346, 419, 499, 586, 680, 781, 889, 1004, 1126, 1255]
? t=[1, 4, 15, 34, 61, 96, 139, 190, 249, 316, 391, 474, 565, 664, 771, 886, 1009, 1140, 1279, 1426]
? d=vector(min(#v,#t),n,t[n]-v[n])
[0, 0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171]
? dd=vector(#d-1, n, d[n+1]-d[n])
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18]

He may have meant something along those lines.
Isn't he on the list?

* Richard Mathar <mathar at strw.leidenuniv.nl> [Aug 01. 2009 08:42]:
>
> I cannot comprehend the meaning of the formula
>    a(n) =A140063 a(n)+n
> in http://research.att.com/~njas/sequences/A054556  .
> I understand that a(n)=4*n^2-9*n+6 and that A140063(n)=7*n^2/2-15*n/2+5 .
> So one could note for example  a(n)=A140063(n)+1+n*(n-3)/2 = A140063(n)+A000217(n-2)
> and may similar relations.
> Is there only some punctuation, some squares or anything else missing
> in the formula?
>
> Richard
>
>
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>
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