A273044 Discriminator of A003095.

1, 2, 5, 9, 10, 10, 17, 29, 29, 29, 47, 47, 47, 61, 71, 71, 71, 101, 109, 121, 121, 121, 121, 139, 139, 139, 139, 139, 139, 139, 139, 139, 139, 274, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278

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 are pairwise incongruent, modulo k.

Links

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

Crossrefs

Cf. A003095

Programs

Maple

N:= 1000: # to get a(1)..a(n)
nmax:= 0:
for m from 1 while nmax <= N do
  a:= 1 mod m; A:= {a};
  for n from 1 while nops(A) = n do
    a:= a^2 +1 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(31)-a(56) from Robert Israel, May 13 2016