cp's OEIS Frontend

A066459 Product of factorials of the digits of n.

%I A066459 #36 Feb 16 2025 08:32:45
%S A066459 1,1,2,6,24,120,720,5040,40320,362880,1,1,2,6,24,120,720,5040,40320,
%T A066459 362880,2,2,4,12,48,240,1440,10080,80640,725760,6,6,12,36,144,720,
%U A066459 4320,30240,241920,2177280,24,24,48,144,576,2880,17280,120960,967680
%N A066459 Product of factorials of the digits of n.
%H A066459 Harry J. Smith and Indranil Ghosh, <a href="/A066459/b066459.txt">Table of n, a(n) for n = 0..10000</a> (first 1001 terms from Harry J. Smith)
%H A066459 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Factorial.html">Factorial</a>
%H A066459 <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>
%F A066459 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
%e A066459 a(24) = (2!) * (4!) = 2 * 24 = 48.
%p A066459 A066459 := proc(n)
%p A066459     local a,d;
%p A066459     a := 1 ;
%p A066459     for d in convert(n,base,10) do
%p A066459         a := a*d! ;
%p A066459     end do:
%p A066459     a ;
%p A066459 end proc: # _R. J. Mathar_, Aug 07 2014
%t A066459 Table[Times@@(IntegerDigits[n]!),{n,0,50}] (* _Harvey P. Dale_, Oct 20 2024 *)
%o A066459 (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
%o A066459 (Haskell)
%o A066459 import Data.List (unfoldr)
%o A066459 a066459 = product . map a000142 .
%o A066459    unfoldr (\x -> if x == 0 then Nothing else Just $ swap $ divMod x 10)
%o A066459 -- _Reinhard Zumkeller_, Oct 11 2011
%o A066459 (Python)
%o A066459 import math
%o A066459 def A066459(n):
%o A066459     s=1
%o A066459     for i in str(n):
%o A066459         s*=math.factorial(int(i))
%o A066459     return s # _Indranil Ghosh_, Jan 11 2017
%Y A066459 Cf. A000142, A034879 (iterated).
%K A066459 base,easy,nonn
%O A066459 0,3
%A A066459 _Jason Earls_, Jan 02 2002