If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 5-subsets of X containing none of X_i, (i=1,...n).

A130811

If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 5-subsets of X containing none of X_i, (i=1,...n).

Terms

    a(0) =32a(1) =192a(2) =672a(3) =1792a(4) =4032a(5) =8064a(6) =14784a(7) =25344a(8) =41184a(9) =64064a(10) =96096a(11) =139776a(12) =198016a(13) =274176a(14) =372096a(15) =496128a(16) =651168a(17) =842688a(18) =1076768a(19) =1360128a(20) =1700160a(21) =2104960a(22) =2583360a(23) =3144960a(24) =3800160a(25) =4560192a(26) =5437152a(27) =6444032a(28) =7594752a(29) =8904192

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