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A098923 33-gonal numbers: n(31n-29)/2. 4
0, 1, 33, 96, 190, 315, 471, 658, 876, 1125, 1405, 1716, 2058, 2431, 2835, 3270, 3736, 4233, 4761, 5320, 5910, 6531, 7183, 7866, 8580, 9325, 10101, 10908, 11746, 12615, 13515, 14446, 15408, 16401, 17425, 18480, 19566, 20683, 21831, 23010 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Similar to 21-gonal and 15-gonal numbers.

LINKS

Table of n, a(n) for n=0..39.

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(n) = n(31n-29)/2.

G.f.: x*(1+30*x)/(1-x)^3. - Bruno Berselli, Feb 04 2011

a(n) = 31*n + a(n-1) - 30 (with a(0)=0). - Vincenzo Librandi, Nov 16 2010

MATHEMATICA

Table[n(31n - 29)/2, {n, 0, 40}] (* Stefan Steinerberger, Feb 15 2006 *)

PolygonalNumber[33, Range[0, 40]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 02 2018 *)

PROG

(PARI) a(n)=n*(31*n-29)/2 \\ Charles R Greathouse IV, Oct 16 2015

CROSSREFS

Cf. n-gonal numbers A000217, A000290, A000326, A000566, A000567, A001106, A001107, A051682, A051624, A051865-A051876, A098924, A098140, A098230.

Sequence in context: A316799 A165378 A098938 * A044220 A044601 A195315

Adjacent sequences:  A098920 A098921 A098922 * A098924 A098925 A098926

KEYWORD

nonn,easy

AUTHOR

Parthasarathy Nambi, Oct 18 2004

EXTENSIONS

More terms from Stefan Steinerberger, Feb 15 2006

STATUS

approved

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Last modified November 16 04:52 EST 2018. Contains 317252 sequences. (Running on oeis4.)