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A293246 a(n) is the smallest k > 1 such that A000166(k) is divisible by n!. 0
2, 2, 3, 7, 25, 121, 241, 1681, 13441, 40321, 403201, 2016001, 3225601, 41932801, 609638401 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(n) is the smallest k > 1 such that round(k!/e) is divisible by n!.

Terms are 0! + 1, 1! + 1, 2! + 1, 3! + 1, 4! + 1, 5! + 1, 6!/3 + 1, 7!/3 + 1, ...

LINKS

Table of n, a(n) for n=0..14.

EXAMPLE

a(3) = 7 because the smallest nonzero subfactorial number that is divisible by 3! is A000166(7) = 1854.

MAPLE

f:= proc(n) local k, t, p;

p:= n!;

t:= 0;

for k from 2 do

  t:= k*t + (-1)^k mod p;

  if t = 0 then return k fi

od:

end proc:

seq(f(n), n=0..13); # Robert Israel, Oct 03 2017

CROSSREFS

Cf. A000142, A000166.

Sequence in context: A083701 A076996 A139148 * A185387 A038507 A077001

Adjacent sequences:  A293243 A293244 A293245 * A293247 A293248 A293249

KEYWORD

nonn,more

AUTHOR

Altug Alkan, Oct 03 2017

EXTENSIONS

a(8)-a(14) from Robert Israel, Oct 03 2017

STATUS

approved

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Last modified November 18 13:22 EST 2018. Contains 317306 sequences. (Running on oeis4.)