A120115 Primes p that divide some Euler number E(k) for even k < p-1, but p does not divide E(p-1).

19, 31, 43, 47, 67, 71, 79, 139, 223, 251, 263, 307, 311, 359, 379, 419, 463, 491, 563, 571, 587, 619, 691, 739, 751, 811, 887, 907, 967, 971, 983, 1019, 1031, 1039, 1051, 1151, 1163, 1187, 1223, 1231, 1279, 1283, 1291, 1307, 1319, 1399, 1423, 1427, 1439

Offset: 1

Author

T. D. Noe, Jun 09 2006

Keywords

• nonn

Comments

See A092218 for a list of all primes that divide some E(k) for even k.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000364, A092218.

Programs

Mathematica

q[n_] := PrimeQ[n] && ! Divisible[EulerE[n - 1], n] && AnyTrue[Range[2, n - 2, 2], Divisible[EulerE[#], n] &]; Select[Range[1500], q] (* Amiram Eldar, Apr 07 2021 *)