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A053528 Number of bipartite graphs with 5 edges on nodes {1..n}. 2

%I

%S 0,0,0,0,0,60,1701,14952,81228,331884,1116675,3256407,8500734,

%T 20306286,45093048,94189095,186736368,353904096,644842674,1134910242,

%U 1936817820,3215467584,5207403663,8245956642,12793342716,19481177100,29161079805,42967291185,62393475690

%N Number of bipartite graphs with 5 edges on nodes {1..n}.

%D R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.5.

%H T. D. Noe, <a href="/A053528/b053528.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (11,-55,165,-330,462,-462,330,-165,55,-11,1).

%F a(n) = (n-4)(n-3)(n-2)(n-1)n(n^5+5n^4+5n^3-85n^2-374n-960)/3840.

%F G.f.: x^5*(60+1041*x-459*x^2+411*x^3-129*x^4+21*x^5)/(1-x)^11. [_Colin Barker_, May 08 2012]

%Y Cf. A000217 (1 edge), A050534 (2 edges), A053526 (3 edges), A053527 (4 edges).

%K nonn,easy

%O 0,6

%A _N. J. A. Sloane_, Jan 16 2000

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Last modified November 21 03:20 EST 2018. Contains 317427 sequences. (Running on oeis4.)