A273043 Discriminator of sequence A001566.

1, 3, 3, 7, 37, 37, 37, 37, 37, 37, 59, 59, 59, 59, 73, 73, 73, 73, 73, 97, 97, 97, 137, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 157, 251, 251, 251, 251, 251, 251, 251, 251, 251, 251, 277, 277, 277, 277, 277, 277, 277

Offset: 1

Author

Jeffrey Shallit, May 13 2016

Keywords

• nonn

Comments

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

Links

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

Crossrefs

Cf. A001566.

Programs

Maple

N:= 1000: # to get a(1)..a(n)
nmax:= 0:
for m from 1 while nmax <= N do
  a:= 3 mod m; A:= {a};
  for n from 1 while nops(A) = n do
    a:= a^2 - 2 mod m;
    A:= A union {a};
  od:
  for k from nmax+1 to n-1 do v[k]:= m od:
  nmax:= max(nmax,n-1);
od:
seq(v[k],k=1..N); # Robert Israel, May 13 2016

Extensions

a(13)-a(28) from Tom Edgar, May 13 2016

a(29)-a(57) from Robert Israel, May 13 2016