A377540 Numbers k such that at least one of the numbers 6k-1 or 6k+1 is prime.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 25, 26, 27, 28, 29, 30, 32, 33, 35, 37, 38, 39, 40, 42, 43, 44, 45, 46, 47, 49, 51, 52, 53, 55, 56, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 72, 73, 74, 75, 76, 77, 78, 80, 81, 82, 83, 84, 85, 87

Offset: 1

Author

Michel Eduardo Beleza Yamagishi, Oct 31 2024

Keywords

• nonn
• easy

Crossrefs

Union of A024898 and A024899.

Cf. A002476, A007528.

Complement of A060461 (with respect to the positive integers) or A171696 (with respect to the nonnegative integers).

Programs

Mathematica

Select[Range[100], PrimeQ[6 # - 1] || PrimeQ[6 # + 1] &]

PARI

isok(k) = isprime(6*k-1) || isprime(6*k+1); \\ Michel Marcus, Oct 31 2024