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A119209 Numbers k such that the k-th triangular number contains only digits {4,5,9}. 2

%I #7 Jul 13 2021 21:30:18

%S 9,10,34,109,314,334,1090,3334,33334,141109,333334,436909,3333334,

%T 4369314,31609965,33166234,33333334,333333334,3333333334,3464100314,

%U 33316662334,33333333334,104828011090,301512701090,333333333334

%N Numbers k such that the k-th triangular number contains only digits {4,5,9}.

%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr459.html">Tridigital Triangular Numbers</a>

%Y Cf. A000217, A119208. See A119034 for a table of cross-references.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, May 10 2006

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Last modified April 25 10:51 EDT 2024. Contains 371967 sequences. (Running on oeis4.)