A363353 Numbers k such that 10^k + 3 is a semiprime.

3, 4, 7, 8, 10, 15, 16, 21, 27, 30, 37, 42, 43, 54, 66, 77, 96, 114, 130, 132, 155, 156, 168, 182, 213, 294

Offset: 1

Author

Robert Israel, Aug 16 2023

Keywords

• nonn
• more

Comments

a(27) >= 306. - Amiram Eldar, Aug 17 2023

Examples

			a(3) = 7 is a term because 10^7 + 3 = 13 * 769231 is a semiprime.
		

Crossrefs

Cf. A001358, A049054, A363352.

Programs

Maple

select(t -> numtheory:-bigomega(10^t+3) = 2, [$1..70]);

Extensions

a(18)-a(26) from Amiram Eldar, Aug 17 2023