Triangle of Bessel numbers read by rows: T(n,k) is the number of k-matchings of the complete graph K(n).

A100861

Triangle of Bessel numbers read by rows: T(n,k) is the number of k-matchings of the complete graph K(n).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =1a(7) =6a(8) =3a(9) =1a(10) =10a(11) =15a(12) =1a(13) =15a(14) =45a(15) =15a(16) =1a(17) =21a(18) =105a(19) =105a(20) =1a(21) =28a(22) =210a(23) =420a(24) =105a(25) =1a(26) =36a(27) =378a(28) =1260a(29) =945

External references