A194265 Smallest product of two distinct primes of the form n*k+1.

6, 15, 91, 65, 341, 91, 1247, 697, 703, 341, 1541, 481, 4187, 1247, 1891, 1649, 14111, 703, 43739, 2501, 5461, 1541, 6533, 7081, 15251, 4187, 17767, 3277, 13747, 1891, 116003, 18721, 13333, 14111, 14981, 2701, 33227, 43739, 12403, 9881, 61337, 5461, 74563

Offset: 1

Author

Omar E. Pol, Sep 03 2011

Keywords

• nonn

Examples

			a(1) = 2*3 = 6
a(2) = 3*5 = 15
a(3) = 7*13 = 91
a(4) = 5*13 = 65
a(5) = 11*31 = 341
		

Crossrefs

Cf. A193869, A193879.

Programs

Mathematica

Table[ps = Select[Table[n*k + 1, {k, 100}], PrimeQ, 2]; If[Length[ps] == 2, ps[[1]]*ps[[2]], 0], {n, 100}] (* T. D. Noe, Oct 21 2011 *)