OFFSET
1,1
EXAMPLE
Number 172 is in sequence because 1*7*2=14, 1*4=4.
MATHEMATICA
cn4Q[n_]:=NestWhile[Times@@IntegerDigits[#]&, n, #>9&]==4; Select[Select[ Range[ 1200], CompositeQ], cn4Q] (* Harvey P. Dale, Apr 28 2018 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Nov 13 2011
STATUS
approved