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A058409
Number of 4 X n nonnegative integer matrices with all column sums 3, up to row and column permutation.
3
1, 3, 18, 92, 458, 1982, 7928, 28592, 95138, 292993, 845027, 2295322, 5915631, 14535676, 34224682, 77510148, 169459010, 358698558, 737106306, 1473867060, 2873564862, 5472731212, 10198198452, 18621343624, 33361303957, 58713103696
OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,-1,-10,0,6,41, -4,-75,-60,-4,236, 161,-140,-395,-410, 390,750,505,-440, -1365,-540,610,1600, 890,-992,-1512,-992, 890,1600,610,-540, -1365,-440,505,750, 390,-410,-395,-140, 161,236,-4,-60, -75,-4,41,6,0, -10,-1,4,-1).
FORMULA
G.f.: 1 / 24*(1 / (1 - x)^20 + 6 / (1 - x)^6 / (1 - x^2)^7 + 3 / (1 - x^2)^10 + 8 / (1 - x)^2 / (1 - x^3)^6 + 6 / (1 - x^4)^5).
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Nov 25 2000
EXTENSIONS
More terms from Max Alekseyev, Jun 21 2011
STATUS
approved