A068200 - OEIS

A068200

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

1, 2, 6, 24, 120, 696, 4536, 32568, 254136, 2133816, 19130040, 182000952, 1828296888, 19311334200, 213709376184, 2470302259512, 29746381049016, 372270346391352, 4831940144914104, 64925998174811448, 901626111996723384, 12920858504042924856

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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)) * 4) end:

a:= n-> `if`(n<=1, n+1, 6*g(n-2)): seq (a(n), n=0..25); # Sean A. Irvine, Feb 02 2024

CROSSREFS

Cf. A000110, A001861, A068199, this, A068201, ..., A000142.

Sequence in context: A214611 A177528 A177527 * A189847 A189284 A274970

Adjacent sequences: A068197 A068198 A068199 * A068201 A068202 A068203

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 23 2002

EXTENSIONS

More terms from Sean A. Irvine, Feb 02 2024

STATUS

approved