A119036 Numbers k such that the k-th triangular number contains only digits {0,1,3}.

1, 2, 4, 24, 77, 141, 778, 1421, 1435, 1620, 14220, 15035, 45453, 148533, 148546, 249122, 471404, 791597, 4497399, 2580747997, 47180737658, 148411814220, 244989930458, 447283652733, 1422190795997, 2581981034024

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base

Links

• G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119035. See A119034 for a table of cross-references.

Programs

Magma

[n: n in [1..2*10^7] | Set(Intseq(Binomial(n+1, 2))) subset [0, 1, 3]]; // Vincenzo Librandi, Oct 07 2015

Mathematica

Select[Range[2 10^7], Complement[IntegerDigits[Binomial[# + 1, 2]], {0, 1, 3}] == {}&] (* Vincenzo Librandi, Oct 07 2015 *)