A319613 a(n) = prime(n) * prime(2n).

6, 21, 65, 133, 319, 481, 731, 1007, 1403, 2059, 2449, 3293, 4141, 4601, 5311, 6943, 8201, 9211, 10921, 12283, 13213, 15247, 16517, 19847, 22213, 24139, 25853, 28141, 29539, 31753, 37211, 40741, 43429, 46843, 52001, 54209, 58561, 62429, 66299, 70757, 75359

Offset: 1

Author

Gus Wiseman, Jan 07 2019

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A001358, A018819, A031215, A031368, A056239, A087897, A101417, A112798, A120641, A320340, A323092, A323093, A323094.

Programs

Maple

a:= n-> (p-> p(n)*p(2*n))(ithprime):
seq(a(n), n=1..50);  # Alois P. Heinz, Jan 08 2019

Mathematica

Table[Prime[n]*Prime[2*n],{n,50}]

PARI

a(n) = prime(n)*prime(2*n) \\ Felix Fröhlich, Jan 09 2019