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 A033583 a(n) = 10*n^2. 29

%I

%S 0,10,40,90,160,250,360,490,640,810,1000,1210,1440,1690,1960,2250,

%T 2560,2890,3240,3610,4000,4410,4840,5290,5760,6250,6760,7290,7840,

%U 8410,9000,9610,10240,10890,11560,12250,12960,13690,14440,15210,16000,16810

%N a(n) = 10*n^2.

%C 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

%C 10 times the squares. - _Omar E. Pol_, Dec 13 2008

%C 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

%H Nathaniel Johnston, <a href="/A033583/b033583.txt">Table of n, a(n) for n = 0..10000</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).

%F a(n) = A000290(n)*10 = A001105(n)*5 = A033429(n)*2. - _Omar E. Pol_, Dec 13 2008

%F a(n) = A158187(n) - 1. - _Reinhard Zumkeller_, Mar 13 2009

%F a(n) = 20*n + a(n-1) - 10 for n>0, a(0)=0. - _Vincenzo Librandi_, Aug 05 2010

%F 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

%p seq(10*n^2,n=0..41); # _Nathaniel Johnston_, Jun 26 2011

%t 10*Range[0,50]^2 (* _Harvey P. Dale_, Apr 20 2011 *)

%o (PARI) a(n)=10*n^2 \\ _Charles R Greathouse IV_, Jun 17 2017

%Y Cf. A000217, A000290, A001105, A033428, A033429, A033581.

%K nonn,easy

%O 0,2

%A _N. J. A. Sloane_

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Last modified October 23 16:46 EDT 2019. Contains 328373 sequences. (Running on oeis4.)