A159229 1/16 the number of n X n arrays of squares of integers with every 2X2 subblock summing to 30

3, 11, 29, 77, 189, 509, 1277, 3581, 9213, 26621, 69629, 204797, 540669, 1605629, 4259837, 12713981, 33816573, 101187581

Offset

2,1

Links

Table of n, a(n) for n=2..19.

Formula

Empirical (for n>=2): a(n) = 2^(3*(n-3)/2) * ((2*sqrt(2)-3)*(-1)^n + 2*sqrt(2) + 3) + 2^n-3. - Vaclav Kotesovec, Nov 30 2012

Empirical G.f.: 7/4+x/4 + (7 - 20*x - 57*x^2 + 154*x^3)/(4*(-1+x)*(-1+2*x)*(-1+8*x^2)). - Vaclav Kotesovec, Nov 30 2012

Crossrefs

Sequence in context: A072610 A110954 A000251 * A239713 A122023 A259594

Adjacent sequences: A159226 A159227 A159228 * A159230 A159231 A159232

Keyword

nonn

Author

R. H. Hardin Apr 06 2009

Status

approved