A216445 a(n) = !n mod n!!.

0, 0, 1, 2, 1, 14, 25, 69, 241, 251, 2481, 6830, 4921, 119547, 250489, 780584, 8507745, 5562314, 2246113, 592853256, 853522921, 1510777190, 67329163881, 131984971712, 1849868497489, 132447220974, 29144172315025, 92977949123774, 608057424846873, 1214694444952016

Offset

0,4

Comments

!n is a subfactorial number (A000166).

n!! is a double factorial number (A006882).

Links

Indranil Ghosh, Table of n, a(n) for n = 0..800

Indranil Ghosh, Python Program to generate the b-file

Example

a(6) = !6 mod 6!! = 265 mod 48 = 25. - Indranil Ghosh, Feb 15 2017

Maple

sf:= proc(n) option remember; n*procname(n-1)+(-1)^n end proc:
sf(0):= 1:
df:= proc(n) option remember; n*procname(n-2) end proc:
df(0):= 1: df(1):= 1:
map(t -> sf(t) mod df(t), [$0..50]); # Robert Israel, Nov 16 2017

Mathematica

Table[Mod[Subfactorial[n], n!!], {n, 0, 30} ]

Crossrefs

Cf. A006882, A000166.

Sequence in context: A245733 A276851 A080346 * A124026 A106204 A290603

Adjacent sequences: A216442 A216443 A216444 * A216446 A216447 A216448

Keyword

nonn

Author

Michel Lagneau, Sep 07 2012

Status

approved