A335031 Complement of A334919.

1, 2, 3, 4, 6, 7, 10, 11, 12, 14, 15, 19, 20, 22, 24, 26, 27, 31, 32, 34, 35, 36, 39, 42, 46, 47, 50, 52, 54, 55, 59, 60, 64, 66, 67, 70, 71, 74, 75, 76, 80, 87, 90, 91, 92, 94, 99, 102, 104, 110, 111, 112, 115, 116, 119, 122, 124, 126, 127, 131, 132, 136

Offset: 1

Author

Davide Rotondo, May 20 2020

Keywords

• nonn

Comments

For each term m belonging to this list, 3*m+1 or (3*m+1)/2 is a prime.

Examples

			1, 2, 3, 4, are terms because for i,j >= 1, number 3*i*j+i+j >= 5, and for i,j >= 2, number 3*i*j-i-j >= 8.
		

Crossrefs

Cf. A334919.

Programs

Magma

[m:m in [1..140]|not exists(a){i:i in [1..m-1]|IsIntegral((m-i)/(1+3*i))} and not exists(b){j:j in [2..m-1]|IsIntegral((m+j)/(-1+3*j)) and (m+j)/(-1+3*j) ge 2}]; // Marius A. Burtea, Jun 04 2020