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

0,2

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

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

Prog

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

Crossrefs

Cf. A192453.

Sequence in context: A047224 A127817 A199173 * A103557 A210963 A210965

Adjacent sequences: A047229 A047230 A047231 * A047233 A047234 A047235

Keyword

easy,nonn

Author

Henry Bottomley, Jun 08 2000

Status

approved