OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
E.g. 27 -> 2*7 = 14 -> 1*4 = 4 is a square.
MATHEMATICA
ipdQ[n_]:=MemberQ[{9, 4, 1}, NestWhile[Times@@IntegerDigits[#]&, n, #>9&]]; Select[Range[700], ipdQ] (* Harvey P. Dale, Apr 15 2018 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
EXTENSIONS
Extended (and corrected) by Patrick De Geest, Jun 15 1999
STATUS
approved