A119054 Numbers k such that the k-th triangular number contains only digits {0,2,6}.

3, 11, 36, 363, 1095, 3640, 72396, 2097628, 1119484011, 11489670148, 200329741476, 666663663636, 6666633636651, 11508483829424, 203306006810436

Offset: 1

Author

Giovanni Resta, May 10 2006

Keywords

• nonn
• base
• more

Comments

No other terms below 1.4*10^20. - Max Alekseyev, Aug 26 2013

Links

• G. Resta, Tridigital Triangular Numbers

Crossrefs

Cf. A000217, A119053. See A119034 for a table of cross-references.

Programs

Magma

[n: n in [1..4*10^6] | Set(Intseq(Binomial(n+1, 2))) subset [0, 2, 6]]; // Vincenzo Librandi, Dec 25 2015

Mathematica

Select[Range[2 10^7], Complement[IntegerDigits[Binomial[# + 1, 2]], {0, 2, 6}] == {} &] (* Vincenzo Librandi, Dec 25 2015 *)