A309558 Numbers k such that A001414(k^4+1) is divisible by k.

1, 5, 10, 2095, 5623, 13589, 14047, 19519, 21143, 154249

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Example

10 is in the sequence because the prime factorization of 10^4+1=10001 is 73*137 and 73+137=210 is divisible by 10.

Maple

filter:= proc(n) local F, t, y;
  F:= ifactors(n^4+1)[2];
  y:= add(t[1]*t[2], t=F);
  y mod n = 0
end proc:
select(filter, [$1..200000]);

Crossrefs

Cf. A001414, A309534, A309542, A309544.

Sequence in context: A298502 A201026 A213146 * A346104 A087463 A160366

Adjacent sequences: A309555 A309556 A309557 * A309559 A309560 A309561

Keyword

nonn,more

Author

J. M. Bergot and Robert Israel, Aug 07 2019

Status

approved