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

1,1

Comments

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

Links

Table of n, a(n) for n=1..26.

Example

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

Maple

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

Crossrefs

Cf. A001358, A049054, A363352.

Sequence in context: A213363 A212123 A213373 * A332059 A229081 A070874

Adjacent sequences: A363350 A363351 A363352 * A363354 A363355 A363356

Keyword

nonn,more

Author

Robert Israel, Aug 16 2023

Extensions

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

Status

approved