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Search: id:A052365
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A052365 Number of nonnegative integer 3 X 3 matrices with sum of elements equal to n, under row and column permutations. +0
7
1, 1, 4, 10, 24, 51, 114, 219, 424, 768, 1352, 2278, 3759, 5978, 9328, 14181, 21164, 30943, 44560, 63063, 88088, 121321, 165152, 222157, 295857, 389948, 509456, 659697, 847552, 1080452, 1367814, 1719652, 2148596, 2668107, 3294676, 4046069 (list; graph; listen)
OFFSET

0,3

COMMENT

Also Molien series for group of structure S_3 X S_3 = (Z_3 X Z_3).O_2^+(3) and order 36, corresponding to complete weight enumerators of Hermitian self-dual GF(3)-linear codes over GF(9) containing the all-ones vector.

LINKS

G. Nebe, E. M. Rains and N. J. A. Sloane, Self-Dual Codes and Invariant Theory, Springer, Berlin, 2006.

Index entries for Molien series

FORMULA

G.f.: -(x^10+2*x^8+x^7+7*x^6-3*x^5+4*x^3+x^2-2*x+1) / ((x^4-x^3+x-1)*(x^3-1)^3*(x+1)^3*(x-1)^5).

Another form for g.f.: u1/u2, where u1 := 1 + x + 2*x^3 + 10*x^4 + 17*x^5 + 19*x^6 + 20*x^7 + 29*x^8 + 37*x^9 + 34*x^10 + 23*x^11 + 12*x^12 + 7*x^13 + 3*x^14 + x^15 u2 := (1-x^2)^4*(1-x^3)^4*(1-x^6);

CROSSREFS

Cf. A002724, A053307, A052366, A052267, A092091.

Sequence in context: A128516 A022569 A093831 this_sequence A107659 A162588 A080615

Adjacent sequences: A052362 A052363 A052364 this_sequence A052366 A052367 A052368

KEYWORD

nonn

AUTHOR

Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 08 2000

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Last modified December 19 12:50 EST 2009. Contains 171053 sequences.


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