A114779 Cumulative product of quadruple factorial A007662.

1, 1, 2, 6, 24, 120, 1440, 30240, 967680, 43545600, 5225472000, 1207084032000, 463520268288000, 271159356948480000, 455547719673446400000, 1578472848668491776000000, 9698137182219213471744000000

Offset

0,3

Links

Table of n, a(n) for n=0..16.

Eric Weisstein's World of Mathematics, Multifactorial.

Formula

a(n) = Product_{j=0..n} j!!!!.

a(n) = Product_{j=0..n} A007662(j).

a(n) = n!!!! * a(n-1) where a(0) = 1, a(1) = 1 and n >= 2.

a(n) = n*(n-4)!!!! * a(n-1) where a(0) = 1, a(1) = 1, a(2) = 2.

Example

a(10) = 1!!!! * 2!!!! * 3!!!! * 4!!!! * 5!!!! * 6!!!! * 7!!!! * 8!!!! * 9!!!! * 10!!!! = 1 * 2 * 3 * 4 * 5 * 12 * 21 * 32 * 45 * 120 = 5225472000 = 2^13 * 3^6 * 5^3 * 7.

Crossrefs

Cf. A006882, A007662, A000178, A114347.

Sequence in context: A347064 A037992 A335386 * A317681 A230363 A358500

Adjacent sequences: A114776 A114777 A114778 * A114780 A114781 A114782

Keyword

easy,nonn

Author

Jonathan Vos Post, Feb 18 2006

Status

approved