A113524 Semiprimes in A056106.

25, 141, 185, 235, 291, 753, 851, 955, 1565, 1851, 2495, 3235, 3641, 4295, 5251, 5765, 6031, 6865, 8061, 9353, 9691, 10741, 11103, 14215, 14631, 15481, 16355, 16801, 17711, 21085, 25855, 27553, 28131, 28715, 29305, 29901

Offset

1,1

Comments

Intersection of A056106 and A001358.

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Example

a(1) = 25 because A056106(3) = 25 = 5^2 is semiprime.
a(36) = 29901 because A056106(100) = 29901 = 3 * 9967 is semiprime.

Mathematica

Select[Array[3 #^2 - # + 1 &, 100], PrimeOmega[#] == 2 &] (* Michael De Vlieger, Mar 17 2021 *)

Crossrefs

Cf. A001358, A056106.

Cf. A113519, A113525, A113527, A113528, A113530.

Sequence in context: A195977 A233368 A240415 * A147505 A147360 A147223

Adjacent sequences: A113521 A113522 A113523 * A113525 A113526 A113527

Keyword

easy,nonn

Author

Jonathan Vos Post, Jan 12 2006

Status

approved