Triangular array T(n,k) read by rows: number of labeled relations of the n-set with exactly k connected components.

A191249

Triangular array T(n,k) read by rows: number of labeled relations of the n-set with exactly k connected components.

Terms

    a(0) =2a(1) =12a(2) =4a(3) =432a(4) =72a(5) =8a(6) =61344a(7) =3888a(8) =288a(9) =16a(10) =32866560a(11) =665280a(12) =21600a(13) =960a(14) =32a(15) =68307743232a(16) =407306880a(17) =4328640a(18) =95040a(19) =2880a(20) =64a(22) =965518299648a(23) =2948037120a(24) =21893760a(25) =362880a(26) =8064a(27) =128

External references