A112393 - OEIS

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A112393

Semiprimes n such that 3*n - 2 is a square.

6, 9, 22, 34, 57, 86, 121, 134, 177, 209, 226, 262, 321, 386, 482, 706, 737, 1046, 1241, 1282, 1366, 1497, 1681, 1977, 2582, 2641, 2761, 3202, 3334, 3401, 3746, 3817, 3961, 4034, 4486, 4881, 5377, 5462, 5721, 6166, 6722, 6817, 7009, 7401, 7601, 7702, 8857

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[10000], PrimeOmega[#]==2&&IntegerQ[Sqrt[3#-2]]&] (* Harvey P. Dale, Mar 28 2018 *)

PROG

(PARI) for(i=1, 15000, if(bigomega(i)==2&&issquare(3*i-2), print1(i, ", "))) (Herrgesell)

CROSSREFS

Cf. A112392.

Sequence in context: A242756 A268665 A043883 * A006132 A033705 A033704