

A119112


Numbers n such that the nth triangular number contains only digits {1,3,4}.


2



1, 2, 53, 258, 25746, 53746, 161946, 7930238, 14927378, 29810546, 4714751561, 25742623453
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OFFSET

1,2


COMMENTS

Next entry must be greater than 1.4*10^16.


LINKS

Table of n, a(n) for n=1..12.
G. Resta, Tridigital Triangular Numbers


MATHEMATICA

(Sqrt[8#+1]1)/2&/@Table[Select[FromDigits/@Tuples[{1, 3, 4}, n], OddQ[ Sqrt[ 8#+1]]&], {n, 21}]//Flatten (* Harvey P. Dale, Jul 09 2017 *)


CROSSREFS

Cf. A000217, A119111. See A119034 for a table of crossreferences.
Sequence in context: A123005 A281227 A142477 * A109791 A265441 A119777
Adjacent sequences: A119109 A119110 A119111 * A119113 A119114 A119115


KEYWORD

nonn,base,more


AUTHOR

Giovanni Resta, May 10 2006


STATUS

approved



