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A119073 Triangular numbers composed of digits {0,4,6}. 2
6, 66, 406, 666, 66066, 446040, 600060, 46046406, 440466040, 4040600460, 6604444400406, 4440066066400004040, 644006046066000066046, 44464646466606404046664666, 464440406444064040044646006604604066, 660466006640066446666000606004066646 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No other terms below 10^37.

LINKS

Table of n, a(n) for n=1..16.

G. Resta, Tridigital Triangular Numbers

MATHEMATICA

Rest[Select[FromDigits/@Tuples[{0, 4, 6}, 10], IntegerQ[(Sqrt[8 # + 1] - 1)/2] &]] (* Vincenzo Librandi, Dec 18 2015 *)

PROG

(MAGMA) [t: n in [1..2*10^7] | Set(Intseq(t)) subset {0, 4, 6} where t is n*(n+1) div 2]; // Vincenzo Librandi, Dec 18 2015

CROSSREFS

Cf. A000217, A058438, A119074.

See A119033 for a table of cross-references.

Sequence in context: A175455 A185253 A192089 * A028559 A249639 A163699

Adjacent sequences:  A119070 A119071 A119072 * A119074 A119075 A119076

KEYWORD

nonn,base

AUTHOR

Giovanni Resta, May 10 2006

EXTENSIONS

Two more terms from Max Alekseyev, May 10 2009

STATUS

approved

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Last modified June 17 13:43 EDT 2021. Contains 345080 sequences. (Running on oeis4.)