A352761 Number of partial order relations on [n] such that 1 and 2 are in the same connected component.

2, 14, 176, 3644, 117860, 5755964, 414823916, 43390462724, 6502296995300, 1380924739533644, 411744185101611356, 170949139294419110804, 98118349844314838731220, 77360523694460582654188124, 83319557470828626639253920716, 121980734453060653381753104078884, 241689591664023311258411470178766020

Offset

2,1

Links

Table of n, a(n) for n=2..18.

Mathematica

nn = 16; A[x_] := Total[Cases[Import["https://oeis.org/A001035/b001035.txt",
      "Table"], {_, _}][[All, 2]]*Table[x^(i - 1)/(i - 1)!, {i, 1, 19}]];
Range[0, nn]! CoefficientList[ Series[D[D[Log[A[x]], x], x] A[x], {x, 0, nn}], x]

Crossrefs

Cf. A001035, A352399.

Sequence in context: A366736 A300282 A336635 * A208195 A252727 A375868

Adjacent sequences: A352758 A352759 A352760 * A352762 A352763 A352764

Keyword

nonn

Author

Geoffrey Critzer, Jul 05 2022

Status

approved