

A069174


Centered 23gonal numbers.


4



1, 24, 70, 139, 231, 346, 484, 645, 829, 1036, 1266, 1519, 1795, 2094, 2416, 2761, 3129, 3520, 3934, 4371, 4831, 5314, 5820, 6349, 6901, 7476, 8074, 8695, 9339, 10006
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OFFSET

1,2


LINKS

Ivan Panchenko, Table of n, a(n) for n = 1..1000
E. Weisstein, Centered Polygonal Numbers
Index entries for sequences related to centered polygonal numbers
Index entries for linear recurrences with constant coefficients, signature (3,3,1).


FORMULA

a(n) = (23*n^2  23*n + 2)/2.
a(n) = 23*n+a(n1)23 (with a(1)=1).  Vincenzo Librandi, Aug 08 2010


MATHEMATICA

FoldList[#1 + #2 &, 1, 23 Range@ 45] (* Robert G. Wilson v, Feb 02 2011 *)


PROG

(PARI) a(n)=(23*n^223*n+2)/2 \\ Charles R Greathouse IV, Jun 17 2017


CROSSREFS

Cf. centered polygonal numbers listed in A069190.
Sequence in context: A043934 A087406 A051876 * A124717 A126378 A006352
Adjacent sequences: A069171 A069172 A069173 * A069175 A069176 A069177


KEYWORD

nonn,easy


AUTHOR

Terrel Trotter, Jr., Apr 09 2002


STATUS

approved



