A131491 2*prime(n)!.

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

Offset

1,1

Links

Table of n, a(n) for n=1..12.

Formula

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

Mathematica

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

Crossrefs

Sequence in context: A076030 A348789 A202859 * A286881 A366822 A360498

Adjacent sequences: A131488 A131489 A131490 * A131492 A131493 A131494

Keyword

easy,nonn

Author

Giovanni Teofilatto, Jul 29 2007

Extensions

More terms from Harvey P. Dale, Dec 19 2011

Status

approved