A159357 Number of n X n arrays of squares of integers with every (n-2)X(n-2) subblock summing to 4

13, 3223, 120420, 1313859, 7979037, 34212213, 116257928, 334277285, 847224269, 1945263907, 4124812588, 8191927383, 15400417725, 27631699329, 47624056752, 79259627513, 127918067213, 200906501615, 307976018164, 461935595947

Offset

4,1

Links

R. H. Hardin, Table of n, a(n) for n=4..30

Formula

Empirical G.f.: -17*x^3 - x^3*(17 - 140*x + 3718*x^2 + 90453*x^3 + 347157*x^4 + 218190*x^5 - 9588*x^6 - 3511*x^7 + 224*x^8)/(-1+x)^9. - Vaclav Kotesovec, Nov 30 2012

Crossrefs

Sequence in context: A296174 A220642 A260982 * A221885 A134159 A221851

Adjacent sequences: A159354 A159355 A159356 * A159358 A159359 A159360

Keyword

nonn

Author

R. H. Hardin Apr 11 2009

Status

approved