A331157 Number of iposets (posets with interfaces) with starting interfaces only, with n points.

1, 2, 5, 16, 66, 350

Offset

0,2

Links

Table of n, a(n) for n=0..5.

Uli Fahrenberg, Christian Johansen, Georg Struth, Ratan Bahadur Thapa, Generating Posets Beyond N, arXiv:1910.06162 [cs.FL], 2019.

Crossrefs

The seven sequences in the table of Uli Fahrenberg et al., 2019, are A000112, A003430, A079566, A331156, A331157, A331158, A331159.

Sequence in context: A091139 A084785 A124551 * A005157 A340021 A019502

Adjacent sequences: A331154 A331155 A331156 * A331158 A331159 A331160

Keyword

nonn,more

Author

N. J. A. Sloane, Jan 16 2020, following a suggestion from Michael De Vlieger.

Status

approved