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
Examples
a(3) = 7 is a term because 10^7 + 3 = 13 * 769231 is a semiprime.
Programs
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Maple
select(t -> numtheory:-bigomega(10^t+3) = 2, [$1..70]);
Extensions
a(18)-a(26) from Amiram Eldar, Aug 17 2023
Comments