A368732 Primes whose index is one, another prime number, or a semiprime.

2, 3, 5, 7, 11, 13, 17, 23, 29, 31, 41, 43, 47, 59, 67, 73, 79, 83, 97, 101, 109, 127, 137, 139, 149, 157, 163, 167, 179, 191, 199, 211, 227, 233, 241, 257, 269, 271, 277, 283, 293, 313, 331, 347, 353, 367, 373, 389, 401, 421, 431, 439, 443, 449, 461, 467, 487

Offset: 1

Author

Gus Wiseman, Jan 08 2024

Keywords

• nonn

Crossrefs

For just primes we have A006450, products A076610, strict A302590.

These indices are A037143.

For just semiprimes we have A106349, products A339112, strict A340020.

Products of these primes are A368728, odd A368729, odd strict A340019.

Products of the complementary primes are A368833.

A000607 counts partitions into primes, with ones allowed A034891.

A001358 lists semiprimes, squarefree A006881.

A056239 adds up prime indices, row sums of A112798.

A101048 counts partitions into semiprimes.

A322551 lists primes of squarefree semiprime index.

Cf. A000040, A000720, A001222, A003963, A005117, A302242, A309356, A320628, A320911, A320912, A339113.

Programs

Mathematica

Prime/@Select[Range[100],PrimeOmega[#]<=2&]