References to A069133

Centered 20-gonal (or icosagonal) numbers.
1, 21, 61, 121, 201, 301, 421, 561, 721, 901, 1101, 1321, 1561, 1821, 2101, 2401

2 seqfan posts

Tue Jul 26 02:52:43 CEST 2011    [seqfan] Re: A193376 Tabl = 20 existing sequences
Thu Dec 2 18:16:11 CET 2010    [seqfan] Re: Trotter Math
Index of A-numbers in seqfan: by ascending order    by month    by frequency    by keyword
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