A338049 a(n) is the smallest prime that is not less than prime(n) and is such that prime(n)*a(n)+2 is semiprime.

2, 11, 11, 7, 11, 19, 17, 29, 29, 29, 37, 37, 43, 43, 61, 53, 61, 71, 89, 79, 73, 79, 83, 103, 97, 103, 107, 109, 113, 127, 131, 151, 137, 151, 157, 197, 167, 167, 173, 181, 211, 199, 191, 197, 199, 211, 227, 257, 257, 241, 233, 251, 257, 251, 263, 263, 269

Offset

1,1

Comments

Motivated by a question about arranging square tiles in a rectangle.

Links

Table of n, a(n) for n=1..57.

Crossrefs

Cf. A000040, A001358, A092207, A198327, A338048.

Sequence in context: A109868 A153521 A153650 * A256665 A086862 A345392

Adjacent sequences: A338046 A338047 A338048 * A338050 A338051 A338052

Keyword

nonn

Author

N. J. A. Sloane, Oct 08 2020, based on an email from Todor Szimeonov, Oct 07 2020

Status

approved