

A113588


a(1) = 3, a(n+1) = d!, where d is the sum of decimal digits of a(n).


2




OFFSET

1,1


COMMENTS

The next term, a(6) = 108!, has 175 digits.  If one omits to take the sum of the digits, i.e., a(n+1)=a(n)!, where a(1)=3 is the least starting value that does not lead to a constant sequence, then the first three terms are the same but a(4) has 1747 digits.  M. F. Hasler, Mar 15 2016


LINKS



FORMULA



EXAMPLE

a(2) = 6;
a(3) = 6! = 720;
a(4) = (7+2+0)! = 9! = 362880;
a(5) = 27!.


MAPLE

A007953 := proc(n) add(i, i= convert(n, base, 10)) ; end: A113588 := proc(n) option remember ; if n = 1 then 3; else factorial(A007953(A113588(n1)) ) ; fi; end: for n from 1 to 6 do printf("%d, ", A113588(n)) ; od: # R. J. Mathar, Feb 06 2008


MATHEMATICA

NestList[Factorial@ Total[IntegerDigits@ #] &, 3, 4] (* Michael De Vlieger, Mar 15 2016 *)


PROG



CROSSREFS



KEYWORD

nonn,base


AUTHOR



EXTENSIONS



STATUS

approved



