A197181 - OEIS

%I #9 Jul 07 2019 14:31:11

%S 1,2,3,4,5,6,7,8,9,15,16,18,24,28,36,45,48,60,64,70,72,75,80,84,90,96,

%T 98,128,144,168,175,180,189,192,256,280,288,360,378,384,448,480,486,

%U 567,576,588,640,648,672,675,720,729,756,768,784,840,864,875,882

%N Numbers that are a divisor of the product of the factorials of their digits in decimal representation.

%H Reinhard Zumkeller, <a href="/A197181/b197181.txt">Table of n, a(n) for n = 1..1000</a>

%e a(10)=15: A066459(15) = 1!*5! = 120 = 15 * 8;

%e a(11)=16: A066459(16) = 1!*6! = 720 = 16 * 45;

%e 17 is not a term because 5040 mod 17 = 8, A066459(16) = 5040;

%e a(12)=18: A066459(15) = 1!*8! = 40320 = 18 * 2240.

%t Select[Range[900],IntegerQ[Times@@(IntegerDigits[#]!)/#]&] (* _Harvey P. Dale_, Jul 07 2019 *)

%o (Haskell)

%o import Data.List (elemIndices)

%o a197181 n = a197181_list !! (n-1)

%o a197181_list = map (+ 1) $ elemIndices 0 $

%o    zipWith mod (map a066459 [1..]) [1..]

%Y Cf. A066459, A000142, A188264.

%K nonn,base

%O 1,2

%A _Reinhard Zumkeller_, Oct 11 2011