OFFSET
1,2
LINKS
Giovanni Resta, Tridigital Triangular Numbers.
MATHEMATICA
(Sqrt[8#+1]-1)/2&/@Table[Select[FromDigits/@Tuples[{1, 3, 4}, n], OddQ[ Sqrt[ 8#+1]]&], {n, 21}]//Flatten (* Harvey P. Dale, Jul 09 2017 *)
CROSSREFS
KEYWORD
nonn,base,more
AUTHOR
Giovanni Resta, May 10 2006
EXTENSIONS
a(13) from Tyler Busby, Mar 30 2023
STATUS
approved