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 A033583 a(n) = 10*n^2. 29
 0, 10, 40, 90, 160, 250, 360, 490, 640, 810, 1000, 1210, 1440, 1690, 1960, 2250, 2560, 2890, 3240, 3610, 4000, 4410, 4840, 5290, 5760, 6250, 6760, 7290, 7840, 8410, 9000, 9610, 10240, 10890, 11560, 12250, 12960, 13690, 14440, 15210, 16000, 16810 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Number of edges of a complete 5-partite graph of order 5n, K_n,n,n,n,n. - Roberto E. Martinez II, Oct 18 2001 10 times the squares. - Omar E. Pol, Dec 13 2008 Sequence found by reading the line from 0, in the direction 0, 10, ..., in the square spiral whose vertices are the generalized heptagonal numbers A085787. - Omar E. Pol, Sep 10 2011 LINKS Nathaniel Johnston, Table of n, a(n) for n = 0..10000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = A000290(n)*10 = A001105(n)*5 = A033429(n)*2. - Omar E. Pol, Dec 13 2008 a(n) = A158187(n) - 1. - Reinhard Zumkeller, Mar 13 2009 a(n) = 20*n + a(n-1) - 10 for n>0, a(0)=0. - Vincenzo Librandi, Aug 05 2010 a(n) = t(5*n) - 5*t(n), where t(i) = i*(i+k)/2 for any k. Special case (k=1): a(n) = A000217(5*n) - 5*A000217(n). - Bruno Berselli, Aug 31 2017 MAPLE seq(10*n^2, n=0..41); # Nathaniel Johnston, Jun 26 2011 MATHEMATICA 10*Range[0, 50]^2  (* Harvey P. Dale, Apr 20 2011 *) PROG (PARI) a(n)=10*n^2 \\ Charles R Greathouse IV, Jun 17 2017 CROSSREFS Cf. A000217, A000290, A001105, A033428, A033429, A033581. Sequence in context: A217073 A210376 A060317 * A131037 A071233 A063490 Adjacent sequences:  A033580 A033581 A033582 * A033584 A033585 A033586 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified October 23 08:57 EDT 2019. Contains 328345 sequences. (Running on oeis4.)