A181335 Partial products of A036691.

1, 4, 96, 18432, 31850496, 550376570880, 114126085737676800, 331312591939905257472000, 14427205603578338379772723200000, 10051861189298894268003697526046720000000

Offset

0,2

Comments

Product of the first n compositorial numbers (which are themselves the product of the first n composite numbers). This is to compositorial numbers (A036691), as superfactorials (A000178) are to factorials (A000142).

Links

Table of n, a(n) for n=0..9.

Formula

a(n) = Product_{i=0..n} A036691(i) = Product_{i=0..n} Product_{j=1..i} A002808(j).

Example

a(3) = 1 * 4 * 24 * 192 = (1) * (1*4) * (1*4*6) * (1*4*6*8), since the first 4 composite numbers are (4, 6, 8) and the 0th compositorial is 1.

Mathematica

nn=20; cnos=Complement[Range[nn], Prime[Range[PrimePi[nn]]]]; Rest[ FoldList[ Times, 1, Rest[FoldList[Times, 1, cnos]]]] (* Harvey P. Dale, Jun 28 2011 *)

Crossrefs

Cf. A000142, A000178, A002808, A036691.

Sequence in context: A308146 A203517 A146514 * A098695 A307934 A059201

Adjacent sequences: A181332 A181333 A181334 * A181336 A181337 A181338

Keyword

nonn,easy

Author

Jonathan Vos Post, Jan 28 2011

Status

approved