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%I #12 Sep 08 2022 08:45:25
%S 1,2,4,24,77,141,778,1421,1435,1620,14220,15035,45453,148533,148546,
%T 249122,471404,791597,4497399,2580747997,47180737658,148411814220,
%U 244989930458,447283652733,1422190795997,2581981034024
%N Numbers k such that the k-th triangular number contains only digits {0,1,3}.
%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr013.html">Tridigital Triangular Numbers</a>
%t Select[Range[2 10^7], Complement[IntegerDigits[Binomial[# + 1, 2]], {0, 1, 3}] == {}&] (* _Vincenzo Librandi_, Oct 07 2015 *)
%o (Magma) [n: n in [1..2*10^7] | Set(Intseq(Binomial(n+1, 2))) subset [0, 1, 3]]; // _Vincenzo Librandi_, Oct 07 2015
%Y Cf. A000217, A119035. See A119034 for a table of cross-references.
%K nonn,base
%O 1,2
%A _Giovanni Resta_, May 10 2006
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