Triangular array read by rows. T(n,k) is the number of sets of lists (as in A000262(n)) with exactly k size 2 lists, n >= 0, 0 <= k <= floor(n/2).

A351823

Triangular array read by rows. T(n,k) is the number of sets of lists (as in A000262(n)) with exactly k size 2 lists, n >= 0, 0 <= k <= floor(n/2).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =2a(4) =7a(5) =6a(6) =49a(7) =12a(8) =12a(9) =301a(10) =140a(11) =60a(12) =2281a(13) =1470a(14) =180a(15) =120a(16) =21211a(17) =12642a(18) =2940a(19) =840a(20) =220417a(21) =127736a(22) =41160a(23) =3360a(24) =1680a(25) =2528569a(26) =1527192a(27) =455112a(28) =70560a(29) =15120

External references