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%I #4 Sep 08 2022 08:45:46
%S 6,10,14,15,22,26,33,34,38,46,51,58,62,69,74,82,86,87,91,94,95,106,
%T 118,122,123,134,141,142,145,146,158,159,166,177,178,194,202,206,213,
%U 214,218,226,249,254,262,267,274,278,287,295,298,302,303,314,321,326,334
%N Semiprimes of the form p*(k*p-1) where k > 1 (and p prime).
%C Regarding k = 1: 3 is the only prime p such that p-1 is prime, so 3*(1*3-1) = 6. But 6 is a term for p = 2 and k = 2 (see example), therefore the sequence does not change if k = 1 is allowed in the definition.
%e For p = 2 and k = 2 we have 2*(2*2-1) = 6, so 6 is a term. For p = 3 and k = 6 we have 3*(6*3-1) = 51, so 51 is a term.
%o (Magma) m:=170; { s: p, q in PrimesUpTo(m) | s le 2*m and exists(t){ k: k in [2..p*q div 2] | q eq p*k-1 } where s is p*q };
%Y Subsequence of A006881 (product of two distinct primes).
%K nonn
%O 1,1
%A _Vassilis Papadimitriou_, Jul 02 2009
%E Edited, corrected and extended by _Klaus Brockhaus_, Jul 06 2009
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