A368503 Number of partitions of an n-set into blocks of size <= n/2.

1, 0, 1, 1, 10, 26, 166, 652, 3795, 18755, 112124, 648649, 4163743, 27216840, 190168577, 1376119903, 10468226150, 82744297014, 681863474058, 5830425411936, 51720008131148, 474821737584174, 4506628734688128, 44150936144057758, 445956917001833090, 4638564968368158592

Offset

0,5

Links

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

Formula

a(n) = n! * [x^n] exp( Sum_{1 <= j <= n/2} x^j / j! ).

Mathematica

Table[n! SeriesCoefficient[Exp[Sum[x^j/j!, {j, 1, Floor[n/2]}]], {x, 0, n}], {n, 0, 25}]

Crossrefs

Cf. A000110, A110618, A368502.

Sequence in context: A221568 A092774 A259979 * A235053 A217583 A301606

Adjacent sequences: A368500 A368501 A368502 * A368504 A368505 A368506

Keyword

nonn

Author

Ilya Gutkovskiy, Dec 27 2023

Status

approved