A049572 Primes p such that x^40 = 2 has a solution mod p.

2, 7, 23, 47, 73, 79, 89, 103, 127, 151, 167, 199, 223, 233, 239, 257, 263, 337, 359, 367, 383, 431, 439, 463, 479, 487, 503, 599, 607, 647, 719, 727, 743, 823, 839, 863, 887, 911, 919, 937, 967, 983, 1039, 1063, 1087, 1103, 1217, 1223, 1249, 1279, 1289