A054771 Number of nonnegative integer 3 X 3 matrices with sum of elements equal to n, up to rotational symmetry.

1, 3, 13, 43, 129, 327, 761, 1619, 3238, 6098, 10974, 18930, 31550, 50930, 80030, 122666, 183999, 270525, 390755, 555205, 777287, 1073297, 1463583, 1972533, 2630044, 3471508, 4539660, 5884564, 7565868, 9652788, 12226860, 15381924

Offset

0,2

Links

Andrew Howroyd, Table of n, a(n) for n = 0..1000

Formula

G.f.: (x^8 - 2*x^7 + 6*x^6 + 2*x^5 + 2*x^4 + 2*x^3 + 6*x^2 - 2*x + 1)/((1 - x^4)^2*(1 - x^2)^2*(1 - x)^5).

Crossrefs

Row n=3 of A343874.

Cf. A008610, A054343.

Sequence in context: A247584 A049173 A049156 * A258776 A201710 A019008

Adjacent sequences: A054768 A054769 A054770 * A054772 A054773 A054774

Keyword

easy,nonn

Author

Vladeta Jovovic, May 18 2000

Status

approved