A343279 a(n) = Stirling2(n, floor(n/2)).

1, 0, 1, 1, 7, 15, 90, 301, 1701, 7770, 42525, 246730, 1323652, 9321312, 49329280, 408741333, 2141764053, 20415995028, 106175395755, 1144614626805, 5917584964655, 71187132291275, 366282500870286, 4864251308951100, 24930204590758260, 362262620784874680

Offset

0,5

Comments

Number of partitions of an n-set into floor(n/2) nonempty subsets.

Links

Table of n, a(n) for n=0..25.

Mathematica

Table[StirlingS2[n, Floor[n/2]], {n, 0, 25}] (* Amiram Eldar, Apr 20 2021 *)

Prog

(PARI) a(n) = stirling(n, n\2, 2); \\ Michel Marcus, Apr 20 2021

Crossrefs

Cf. A007820, A048993, A129506, A343278.

Keyword

nonn

Author

Peter Luschny, Apr 20 2021

Status

approved