A273062 Discriminator of the composite numbers A002808.

1, 3, 3, 6, 7, 7, 7, 12, 13, 13, 13, 18, 19, 19, 22, 23, 24, 25, 25, 25, 30, 31, 32, 33, 33, 36, 37, 37, 37, 42, 43, 43, 46, 47, 48, 49, 49, 52, 53, 54, 55, 55, 55, 60, 61, 62, 63, 63, 66, 67, 67, 67, 72, 73, 74, 75, 75, 78, 79, 79, 82, 83, 84, 85, 85, 88, 89, 90, 91, 92, 93, 93, 96, 97, 97, 97, 102, 103, 103, 103, 108, 109, 109, 112, 113

Offset: 1

Author

Jeffrey Shallit, May 14 2016

Keywords

• nonn

Comments

The discriminator of a sequence is the least integer k such that the first n terms are pairwise incongruent, modulo k.

Links

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

Crossrefs

Cf. A002808.

Programs

Maple

R:= 1: y:= 1: C:= remove(isprime, [$1..200]):
for n from 2 to nops(C) do
   do
     S:= convert(C[1..n] mod y, set);
     if nops(S) = n then break fi;
     y:= y+1;
   od;
   R:= R,y;
od:
R; # Robert Israel, Jul 13 2023