A047232 Smallest k > n where n is a 4th power modulo k.

1, 2, 7, 6, 6, 10, 10, 9, 14, 11, 15, 14, 22, 17, 22, 21, 17, 19, 21, 27, 22, 25, 26, 29, 29, 27, 37, 33, 31, 46, 34, 33, 46, 34, 37, 38, 38, 41, 43, 42, 41, 43, 47, 49, 49, 55, 49, 53, 52, 53, 62, 59, 54, 58, 57, 57, 61, 59, 61, 62, 66, 65, 67, 74, 66, 67, 75, 77, 76, 73, 74

Offset: 0

Author

Henry Bottomley, Jun 08 2000

Keywords

• easy
• nonn

Comments

a(n) = n+1 for n+1 in A192453. - Robert Israel, May 24 2019

Links

• Robert Israel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A192453.

Programs

Maple

N:= 100: # for a(0)..a(N)
V:= Array(0..N):
count:= 1: V[0]:= 1:
for k from 2 while count < N+1 do
  R:= select(t -> t <= N and V[t] = 0,{seq(x^4 mod k,x=1..k/2)});
  V[convert(R,list)]:= k;
  count:= count + nops(R);
od:
convert(V,list); # Robert Israel, May 24 2019

PARI

a(n) = {my(k=n+1); while (!ispower(Mod(n,k), 4), k++); k;} \\ Michel Marcus, May 25 2019