A159356 Number of n X n arrays of squares of integers with every (n-1)X(n-1) subblock summing to 4

9, 767, 19252, 182643, 1036981, 4279949, 14199872, 40175697, 100665373, 229182711, 482835464, 954070027, 1786340817, 3194495053, 5490736316, 9117102929, 14685469857, 23026155487, 35246287308, 52799153171, 77565837469

Offset

3,1

Links

R. H. Hardin, Table of n, a(n) for n=3..34

Formula

Empirical (for n>=3): a(n) = 1/288*(519*n^8 - 6716*n^7 + 34142*n^6 - 78248*n^5 + 32735*n^4 + 236596*n^3 - 555412*n^2 + 518112*n - 185184). - Vaclav Kotesovec, Nov 30 2012

Empirical G.f.: -x^2 + x^2*(-1 - 722*x^2 - 12589*x^3 - 36357*x^4 - 22846*x^5 - 692*x^6 + 535*x^7 + 12*x^8)/(-1+x)^9. - Vaclav Kotesovec, Nov 30 2012

Crossrefs

Sequence in context: A145183 A124417 A265463 * A246123 A246124 A223380

Adjacent sequences: A159353 A159354 A159355 * A159357 A159358 A159359

Keyword

nonn

Author

R. H. Hardin Apr 11 2009

Status

approved