# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a014773
Showing 1-1 of 1

%I A014773 #12 Dec 17 2015 09:43:12
%S A014773 1,49,3025,6561,35721,55225,162409,219961,485809,613089,1147041,
%T A014773 1385329,2325625,2725801,4239481,4862025,7144929,8059921,11336689,
%U A014773 12623809,17147881,18896409,24950025,27258841,35153041,38130625,48205249,51969681,64593369,69272329
%N A014773 Squares of odd heptagonal numbers.
%H A014773 Colin Barker, <a href="/A014773/b014773.txt">Table of n, a(n) for n = 1..1000</a>
%H A014773 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,4,-4,-6,6,4,-4,-1,1).
%F A014773 From _Colin Barker_, Dec 17 2015: (Start)
%F A014773 a(n) = 1/2*(200*n^4-920*n^3+1578*n^2-1196*n+338) for n even.
%F A014773 a(n) = 1/2*(200*n^4-520*n^3+498*n^2-208*n+32) for n odd.
%F A014773 G.f.: x*(1+48*x+2972*x^2+3344*x^3+17262*x^4+5648*x^5+8396*x^6+560*x^7+169*x^8) / ((1-x)^5*(1+x)^4).
%F A014773 (End)
%t A014773 Table[SeriesCoefficient[x (1 + 48 x + 2972 x^2 + 3344 x^3 + 17262 x^4 + 5648 x^5 + 8396 x^6 + 560 x^7 + 169 x^8)/((1 - x)^5 (1 + x)^4), {x, 0, n}], {n, 30}] (* _Michael De Vlieger_, Dec 17 2015 *)
%o A014773 (PARI) Vec(x*(1+48*x+2972*x^2+3344*x^3+17262*x^4+5648*x^5+8396*x^6+560*x^7+169*x^8) / ((1-x)^5*(1+x)^4) + O(x^40)) \\ _Colin Barker_, Dec 17 2015
%Y A014773 Cf. A000566, A014637, A014640, A014792.
%K A014773 nonn,easy
%O A014773 1,2
%A A014773 _Mohammad K. Azarian_
%E A014773 More terms from _Erich Friedman_.

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE