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A119052
Numbers k such that the k-th triangular number contains only digits {0,2,5}.
3
10, 100, 224, 714, 1000, 10000, 32410, 67089, 100000, 210010, 1000000, 1019825, 2100010, 2109599, 3231100, 10000000, 21000010, 33173785, 71450010, 100000000, 200101000, 201000100, 210000010, 663702049, 1000000000
OFFSET
1,1
MATHEMATICA
Select[Range[2 10^7], Complement[IntegerDigits[Binomial[# + 1, 2]], {0, 2, 5}] == {}&] (* Vincenzo Librandi, Oct 07 2015 *)
PROG
(Magma) [n: n in [1..2*10^7] | Set(Intseq(Binomial(n+1, 2))) subset [0, 2, 5]]; // Vincenzo Librandi, Oct 07 2015
CROSSREFS
Cf. A000217, A119051. See A119034 for a table of cross-references.
Sequence in context: A101655 A043216 A044342 * A029774 A208375 A208065
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, May 10 2006
STATUS
approved