A068201 One of a family of sequences that interpolates between the Bell numbers and the factorials.

1, 2, 6, 24, 120, 720, 4920, 37320, 309120, 2763720, 26440920, 268864320, 2889978120, 32689371720, 387638491920, 4803456571320, 62026296732120, 832595493624720, 11592967532632920, 167119530011233320, 2489936579950221120, 38283169922493447720

Offset

0,2

References

G. Labelle et al., Stirling numbers interpolation using permutations with forbidden subsequences, Discrete Math. 246 (2002), 177-195.

Links

Table of n, a(n) for n=0..21.

Maple

g:= proc(n) option remember; `if` (n=0, 1, (1+add(binomial (n-1, k-1) * g(n-k), k=1..n-1)) * 5) end:
a:= n-> `if`(n<=2, (n+1)!, 24*g(n-3)): seq (a(n), n=0..25); # Sean A. Irvine, Feb 02 2024

Crossrefs

Cf. A000110, A001861, A068199, A068200, this, ..., A000142.

Sequence in context: A177546 A177544 A177540 * A189848 A189285 A177545

Adjacent sequences: A068198 A068199 A068200 * A068202 A068203 A068204

Keyword

nonn

Author

N. J. A. Sloane, Mar 23 2002

Extensions

More terms from Sean A. Irvine, Feb 02 2024

Status

approved