A395256 Number of transitive relations that are not posets.

0, 1, 10, 152, 3775, 150072, 9285166, 872092671, 121775980244, 24846236879436, 7300839234261505, 3052125264655997158, 1796588694272714470738, 1475890843138637539013961, 1679141073825313100949770814, 2628147606972836865935342526732, 5626092386983993568549192172336375

Offset

0,3

Comments

a(n) counts the transitive relations on n labeled elements that fail to be partial orders (i.e., that violate reflexivity and/or antisymmetry).

Links

Table of n, a(n) for n=0..16.

Formula

a(n) = A006905(n) - A001035(n).

Example

a(1)=1 because the only transitive relations on the 1-set X={1} is the null relation.

Crossrefs

Cf. A006905, A001035.

Sequence in context: A251730 A222487 A307352 * A345348 A349490 A269608

Adjacent sequences: A395253 A395254 A395255 * A395257 A395258 A395259

Keyword

nonn

Author

Firdous Ahmad Mala, Apr 17 2026

Status

approved