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Number of n X n arrays of squares of integers with every (n-1)X(n-1) subblock summing to 6 and every element equal to at least one neighbor.
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%I #7 Dec 18 2015 18:17:14

%S 0,40,5606,41698,158360,453388,1097036,2364072,4672136,8626500,

%T 15071228,25146736,40353752,62623676,94395340,138698168,199241736,

%U 280511732,387872316,527674880,707373208

%N Number of n X n arrays of squares of integers with every (n-1)X(n-1) subblock summing to 6 and every element equal to at least one neighbor.

%F Empirical (for n>=7): a(n) = 80*n^6/9 - 401*n^5/3 + 10112*n^4/9 - 5809*n^3 + 145814*n^2/9 - 64942*n/3 + 11612. - _Vaclav Kotesovec_, Nov 30 2012

%K nonn

%O 3,2

%A _R. H. Hardin_ Apr 14 2009