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%I #12 Sep 08 2022 08:45:25
%S 10,100,224,714,1000,10000,32410,67089,100000,210010,1000000,1019825,
%T 2100010,2109599,3231100,10000000,21000010,33173785,71450010,
%U 100000000,200101000,201000100,210000010,663702049,1000000000
%N Numbers k such that the k-th triangular number contains only digits {0,2,5}.
%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr025.html">Tridigital Triangular Numbers</a>
%t Select[Range[2 10^7], Complement[IntegerDigits[Binomial[# + 1, 2]], {0, 2, 5}] == {}&] (* _Vincenzo Librandi_, Oct 07 2015 *)
%o (Magma) [n: n in [1..2*10^7] | Set(Intseq(Binomial(n+1, 2))) subset [0, 2, 5]]; // _Vincenzo Librandi_, Oct 07 2015
%Y Cf. A000217, A119051. See A119034 for a table of cross-references.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, May 10 2006
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