A146124 Number of n X n arrays of squares of integers summing to 5 with every element equal to at least one neighbor.
0, 32, 516, 2307, 6472, 14379, 27684, 48331, 78552, 120867, 178084, 253299, 349896, 471547, 622212, 806139, 1027864, 1292211, 1604292, 1969507, 2393544, 2882379, 3442276, 4079787
Offset: 2
Keywords
Formula
Empirical (for n>=4): a(n) = 12*n^4 - 36*n^3 - 85*n^2 + 324*n - 188. - Vaclav Kotesovec, Nov 30 2012
Conjectures from Colin Barker, Mar 23 2018: (Start)
G.f.: x^3*(32 + 356*x + 47*x^2 - 223*x^3 + 89*x^4 - 13*x^5) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>8.
(End)