A119063 Triangular numbers composed of digits {0,3,6}.

3, 6, 36, 66, 300, 630, 666, 3003, 66066, 333336, 600060, 630003, 3306306, 30330366, 330360660, 6603360660, 63630666636636, 633663606306030, 63033033630030366, 66000033300360030336, 33363363630036306006003, 363003633036606030300000, 663300330303660363306006

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• Giovanni Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A058432, A119064. See A119033 for a table of cross-references.

Programs

Mathematica

Select[FromDigits/@Tuples[{0,3,6},12],OddQ[Sqrt[8#+1]]&]//Rest (* The program generates the first 16 terms of the sequence. *) (* Harvey P. Dale, Jul 14 2025 *)

Formula

a(n) = A000217(A119064(n)). - Michel Marcus, Mar 22 2023

Extensions

a(22)-a(23) from Tyler Busby, Mar 22 2023