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A275608 Numbers n that divide no nonzero terms of A003422. 3
3, 6, 8, 9, 12, 13, 15, 16, 18, 20, 21, 24, 25, 26, 27, 28, 29, 30, 32, 33, 35, 36, 39, 40, 42, 43, 44, 45, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 63, 64, 65, 66, 67, 68, 69, 70, 72, 75, 76, 78, 79, 80, 81, 83, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that A013584(n) = 0.

If n is in the sequence, then so is every multiple of n.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

3 is in the sequence because A003422(1)=1 and A003422(2)=2 are not divisible by 3, and A003422(k)==1 (mod 3) for k >= 3.

4 is not in the sequence because A003422(3) = 4 is divisible by 4.

MAPLE

filter:= proc(n) local t, r, m;

  r:= 1; t:= 1;

  for m from 1 do

    r:= r*m mod n;

    if r = 0 then return true fi;

    t:= t + r mod n;

    if t = 0 then return false fi;

  od;

end proc:

select(filter, [$2..100]);

MATHEMATICA

okQ[n_] := Module[{t, r, m}, r = 1; t = 1; For[m = 1, True, m++, r = Mod[r*m, n]; If[r == 0, Return[True]]; t = Mod[t + r, n]; If[t == 0, Return[False]]]];

Select[Range[2, 100], okQ] (* Jean-Fran├žois Alcover, Apr 12 2019, after Robert Israel *)

CROSSREFS

Cf. A003422, A013584.

Complement of A049045.

Sequence in context: A167195 A032489 A153769 * A155723 A095277 A185717

Adjacent sequences:  A275605 A275606 A275607 * A275609 A275610 A275611

KEYWORD

nonn

AUTHOR

Robert Israel, Nov 14 2016

STATUS

approved

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Last modified March 31 18:53 EDT 2020. Contains 333151 sequences. (Running on oeis4.)