OFFSET
1,2
COMMENTS
A d-digit number is at least 10^(d-1), its product of digits is at most 9^d, and its sum of digits is at most 9d. For d >= 70, 4 * 10^(d-1) > 9^d * 9d, and so the sequence is finite. (Of course this can be improved.)
MATHEMATICA
Do[ If[ 4n == Apply[ Times, IntegerDigits[n]] Apply[ Plus, IntegerDigits[n]], Print[n]], {n, 0, 10^7} ]
CROSSREFS
KEYWORD
nonn,base,fini
AUTHOR
Robert G. Wilson v, Dec 13 2001
EXTENSIONS
OFFSET changed from 0,2 to 1,2 by Harry J. Smith, Feb 03 2010
STATUS
approved