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 A216369 a(n) = !(n-1) mod n. 1

%I

%S 0,0,1,2,4,2,6,6,1,6,1,2,10,8,4,6,13,8,9,6,13,10,21,14,14,16,10,22,17,

%T 26,2,6,1,4,34,26,5,10,10,6,4,8,16,10,19,2,18,38,48,36,13,42,13,44,34,

%U 22,28,12,28,26,22,60,55,38,49,32,65,38,67,36,68,62

%N a(n) = !(n-1) mod n.

%C !n is a subfactorial number (A000166).

%H Indranil Ghosh, <a href="/A216369/b216369.txt">Table of n, a(n) for n = 1..10000</a>

%e a(7)=6 because !(7-1) = 265, and 265 == 6 mod 7.

%p with(numtheory): f:=n->sum(n!*(((-1)^k)*1/k!), k=0..n):for n from 1 to 150 do: x:=irem(f(n-1),n): printf(`%d, `, x):od:

%Y Cf. A000166, A124625.

%K nonn

%O 1,4

%A _Michel Lagneau_, Sep 05 2012

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Last modified April 24 16:16 EDT 2019. Contains 322430 sequences. (Running on oeis4.)