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A119140 Triangular numbers composed of digits {1,6,7}. 2

%I #9 Mar 22 2023 13:11:39

%S 1,6,66,171,666,1176,1711,17766,61776,67161,166176,617716,7767711,

%T 61677171,77171676,161667171,166777716,611677776,66767167176,

%U 77111161116,171676611666,617617761166,1116177116671,161776717667666676,1116166667661771771,6667177116611677771

%N Triangular numbers composed of digits {1,6,7}.

%H Giovanni Resta, <a href="http://www.numbersaplenty.com/tr/tr167.html">Tridigital Triangular Numbers</a>

%F a(n) = A000217(A119141(n)). - _Michel Marcus_, Mar 22 2023

%Y Cf. A000217, A053907, A119141. See A119033 for a table of cross-references.

%K nonn,base

%O 1,2

%A _Giovanni Resta_, May 10 2006

%E a(24)-a(26) from _Tyler Busby_, Mar 22 2023

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Last modified August 31 19:25 EDT 2024. Contains 375573 sequences. (Running on oeis4.)