A131491 a(n) = 2*prime(n)!.

4, 12, 240, 10080, 79833600, 12454041600, 711374856192000, 243290200817664000, 51704033477769953280000, 17683523987479403909087232000000, 16445677308355845635451125760000000, 27527506182452690092631959163161804800000000

Offset: 1

Author

Giovanni Teofilatto, Jul 29 2007

Keywords

• easy
• nonn
• changed

Crossrefs

Cf. A000040, A000142, A039716.

Programs

Mathematica

2*Prime[Range[15]]! (* Harvey P. Dale, Dec 19 2011 *)

Formula

a(n) = 2*A039716(n) = 2*A000142(A000040(n)). - R. J. Mathar, Jul 31 2007

Extensions

More terms from Harvey P. Dale, Dec 19 2011