A146125 Number of n X n arrays of squares of integers with every (n-1) X (n-1) subblock summing to 5 and every element equal to at least one neighbor.

0, 93, 2046, 8675, 24622, 56389, 112078, 201457, 335974, 528757, 794614, 1150033, 1613182, 2203909, 2943742, 3855889, 4965238, 6298357, 7883494, 9750577, 11931214, 14458693, 17367982, 20695729, 24480262

Offset

3,2

Links

Table of n, a(n) for n=3..27.

Formula

Empirical (for n>=7): a(n) = 70*n^4 - 752*n^3 + 3059*n^2 - 5680*n + 4357. - Vaclav Kotesovec, Nov 30 2012

Conjectures from Colin Barker, Mar 23 2018: (Start)

G.f.: x^4*(93 + 1581*x - 625*x^2 + 777*x^3 + 34*x^4 - 260*x^5 + 66*x^6 + 14*x^7) / (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>11.

(End)

Crossrefs

Sequence in context: A264556 A250373 A250374 * A353002 A017809 A017756

Adjacent sequences: A146122 A146123 A146124 * A146126 A146127 A146128

Keyword

nonn

Author

R. H. Hardin, Apr 14 2009

Status

approved