%I #14 Oct 09 2022 05:20:55

%S 4,49,301,589,973,2353,2701,3073,4333,5293,5809,6349,6913,7501,8749,

%T 9409,10801,11533,13069,14701,15553,16429,23233,24301,25393,27649,

%U 30001

%N Semiprimes in A056107.

%C Intersection of A056107 and A001358.

%H Michael De Vlieger, <a href="/A113525/b113525.txt">Table of n, a(n) for n = 1..10000</a>

%e a(1) = 4 because A056107(1) = 3*1^2 + 1 = 4 = 2^2 is semiprime.

%e a(16) = 9409 because A056107(56) = 3*56^2 + 1 = 9409 = 97^2 is semiprime.

%e a(27) = 30001 because A056107(100) = 3*100^2 + 1 = 30001 = 19 * 1579 is semiprime.

%t Select[Array[3 #^2 + 1 &, 100], PrimeOmega[#] == 2 &] (* _Michael De Vlieger_, Mar 17 2021 *)

%Y Cf. A001358, A056107.

%Y Cf. A113519, A113524, A113527, A113528, A113530.

%K easy,nonn

%O 1,1

%A _Jonathan Vos Post_, Jan 12 2006