OFFSET
1,3
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
46 is in the sequence because (1) it is an enneagonal number and (2) the product of its digits 4*6 = 24 is also an enneagonal number.
MATHEMATICA
pod[n_] := Times @@ IntegerDigits[n]; ennQ[n_] := n == 0 || IntegerQ[(Sqrt[56*n + 25] + 5)/14]; Select[Table[n*(7*n - 5)/2, {n, 0, 120}], ennQ[pod[#]] &] (* Amiram Eldar, Feb 06 2021 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 15 2006
EXTENSIONS
Offset corrected by Amiram Eldar, Feb 06 2021
STATUS
approved