A159225 - OEIS

A159225

1/4 the number of n X n arrays of squares of integers with every 2X2 subblock summing to 25

7, 24, 53, 135, 265, 621, 1169, 2649, 4897, 10929, 20033, 44385, 81025, 178881, 325889, 718209, 1307137, 2878209, 5235713, 11523585, 20957185, 46115841, 83857409, 184506369, 335486977

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OFFSET

2,1

LINKS

Table of n, a(n) for n=2..26.

FORMULA

Conjecture: G.f.: x^2*(-7-12*x^4+20*x^3+13*x^2-17*x)/((x-1)*(2*x+1)*(2*x-1)*(2*x^2-1)) [From Maksym Voznyy (voznyy(AT)mail.ru), Jul 26 2009]

CROSSREFS

Sequence in context: A006707 A196116 A168668 * A146298 A079671 A212511

Adjacent sequences: A159222 A159223 A159224 * A159226 A159227 A159228

KEYWORD

nonn

AUTHOR

R. H. Hardin Apr 06 2009

STATUS

approved