OFFSET
1,1
LINKS
Giovanni Resta, Tridigital Triangular Numbers.
FORMULA
MATHEMATICA
Rest[Select[FromDigits/@Tuples[{0, 5, 9}, 16], OddQ[Sqrt[8#+1]]&]] (* Harvey P. Dale, Apr 14 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, May 10 2006
EXTENSIONS
a(20)-a(21) from Tyler Busby, Mar 23 2023
STATUS
approved