A054773 Number of nonnegative integer 4 X 4 matrices with sum of elements equal to n, up to rotational symmetry.

1, 4, 36, 204, 980, 3876, 13596, 42636, 122666, 326876, 817388, 1931540, 4346404, 9360540, 19390548, 38779380, 75136675, 141430680, 259292440, 463991880, 811990680, 1391975640, 2341057896, 3867821640, 6285222804, 10056336264

Offset

0,2

Links

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

Formula

G.f.: (x^16 - 4*x^15 + 28*x^14 - 12*x^13 + 76*x^12 + 60*x^11 + 196*x^10 - 44*x^9 + 422*x^8 - 44*x^7 + 196*x^6 + 60*x^5 + 76*x^4 - 12*x^3 + 28*x^2 - 4*x + 1)/ ((x - 1)^16*(x + 1)^8*(x^2 + 1)^4).

Crossrefs

Row n=4 of A343874.

Cf. A008610.

Sequence in context: A220436 A144888 A291643 * A074434 A257888 A197424

Adjacent sequences: A054770 A054771 A054772 * A054774 A054775 A054776

Keyword

nonn

Author

Vladeta Jovovic, May 19 2000

Status

approved