A119154 Triangular numbers composed of digits {2,3,6}.

3, 6, 36, 66, 666, 22366, 333336, 23232336, 336662326, 2232222336, 3263633236, 6266233326, 262322266326, 266633626626, 2263263223266, 36226633633326, 66333362366236266, 3236622262232626626666, 3322222636222323322336, 2332636666226262326336266

Offset

1,1

Links

Table of n, a(n) for n=1..20.

Giovanni Resta, Tridigital Triangular Numbers.

Formula

a(n) = A000217(A119155(n)). - Tyler Busby, Mar 28 2023

Mathematica

Select[Flatten[Table[FromDigits/@Tuples[{2, 3, 6}, n], {n, 10}]], OddQ[Sqrt[8#+1]]&] (* The program generates the first 12 terms of the sequence. To generate more, increase the constant after "n, " but the program will take longer to run. *) (* Harvey P. Dale, Apr 18 2020 *)

Crossrefs

Cf. A000217, A058458, A119155. See A119033 for a table of cross-references.

Sequence in context: A119115 A079653 A119063 * A119194 A119198 A119196

Adjacent sequences: A119151 A119152 A119153 * A119155 A119156 A119157

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

a(20) from Tyler Busby, Mar 28 2023

Status

approved