A066459 Product of factorials of the digits of n.

1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 2, 2, 4, 12, 48, 240, 1440, 10080, 80640, 725760, 6, 6, 12, 36, 144, 720, 4320, 30240, 241920, 2177280, 24, 24, 48, 144, 576, 2880, 17280, 120960, 967680

Offset

0,3

Links

Harry J. Smith and Indranil Ghosh, Table of n, a(n) for n = 0..10000 (first 1001 terms from Harry J. Smith)

Eric Weisstein's World of Mathematics, Factorial

Index entries for sequences related to factorial numbers

Formula

If n=10*q+r, (0 <= r < 10) then a(n) = (q+1+r)!*Sum_{k=0..r} (-1)^(q-k)*binomial(r,k)/(q+1+r-k). - Milan Janjic, Dec 14 2008

Example

a(24) = (2!) * (4!) = 2 * 24 = 48.

Maple

A066459 := proc(n)
    local a, d;
    a := 1 ;
    for d in convert(n, base, 10) do
        a := a*d! ;
    end do:
    a ;
end proc: # R. J. Mathar, Aug 07 2014

Prog

(PARI) { for (n=0, 1000, m=n; a=1; while (m>0, d=m%10; m=(m-d)/10; a*=d!); write("b066459.txt", n, " ", a) ) } \\ Harry J. Smith, Feb 15 2010
(Haskell)
import Data.List (unfoldr)
a066459 = product . map a000142 .
   unfoldr (\x -> if x == 0 then Nothing else Just $ swap $ divMod x 10)
-- Reinhard Zumkeller, Oct 11 2011
(Python)
import math
def A066459(n):
    s=1
    for i in str(n):
        s*=math.factorial(int(i))
    return s # Indranil Ghosh, Jan 11 2017

Crossrefs

Cf. A000142, A034879 (iterated).

Sequence in context: A248841 A072132 A230231 * A269221 A071937 A061602

Adjacent sequences: A066456 A066457 A066458 * A066460 A066461 A066462

Keyword

base,easy,nonn

Author

Jason Earls, Jan 02 2002

Status

approved