OFFSET
0,3
EXAMPLE
715 is in the sequence because it is a pentagonal number and the product of its digits 7*1*5=35 is also a pentagonal number.
MATHEMATICA
pn=Table[n (3 n - 1)/2, {n, 0, 90}] ; Select[pn, MemberQ[pn, Times@@IntegerDigits[#]]&] (* James C. McMahon, Sep 25 2024 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 13 2006
STATUS
approved