OFFSET
1,2
LINKS
Giovanni Resta, Tridigital Triangular Numbers.
FORMULA
MATHEMATICA
Flatten[Table[Select[FromDigits/@Tuples[{1, 2, 3}, n], IntegerQ[(Sqrt[ 8#+1]- 1)/2]&], {n, 14}]] (* Harvey P. Dale, May 16 2014 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, May 10 2006
EXTENSIONS
a(23)-a(24) from Tyler Busby, Mar 23 2023
STATUS
approved