A014792 Squares of even heptagonal numbers.
0, 324, 1156, 12544, 21904, 81796, 116964, 291600, 379456, 763876, 940900, 1658944, 1971216, 3175524, 3678724, 5550736, 6310144, 9060100, 10150596, 14017536, 15523600, 20775364, 22791076, 29724304, 32353344, 41293476, 44649124, 55950400, 60155536, 74200996
Offset: 0
Links
- Colin Barker, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (1,4,-4,-6,6,4,-4,-1,1).
Programs
-
Mathematica
Select[Table[(n(5n-3))/2,{n,0,60}],EvenQ]^2 (* Harvey P. Dale, Jul 24 2015 *) -
PARI
concat(0, Vec(4*x*(81+208*x+2523*x^2+1508*x^3+4071*x^4+680*x^5+525*x^6+4*x^7) / ((1-x)^5*(1+x)^4) + O(x^40))) \\ Colin Barker, Dec 17 2015
Formula
From Colin Barker, Dec 17 2015: (Start)
a(n) = (1/2)*(200*n^4 - 120*n^3 + 18*n^2) for n even.
a(n) = (1/2)*(200*n^4 + 280*n^3 + 138*n^2 + 28*n + 2) for n odd.
G.f.: 4*x*(81 + 208*x + 2523*x^2 + 1508*x^3 + 4071*x^4 + 680*x^5 + 525*x^6 + 4*x^7) / ((1-x)^5*(1+x)^4).
(End)
Extensions
More terms from Patrick De Geest, Aug 17 2000