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A119035 Triangular numbers composed of digits {0,1,3}. 2
1, 3, 10, 300, 3003, 10011, 303031, 1010331, 1030330, 1313010, 101111310, 113033130, 1033010331, 11031100311, 11033031331, 31031010003, 111111101310, 313313301003, 10113301131300, 3330130113300130003 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..20.

G. Resta, Tridigital Triangular Numbers

MATHEMATICA

Rest[Select[FromDigits/@Tuples[{0, 1, 3}, 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, 1, 3} where t is n*(n+1) div 2]; // Vincenzo Librandi, Dec 18 2015

CROSSREFS

Cf. A000217, A119036. See A119033 for a table of cross-references.

Sequence in context: A270553 A308657 A156193 * A004100 A103156 A202712

Adjacent sequences:  A119032 A119033 A119034 * A119036 A119037 A119038

KEYWORD

nonn,base

AUTHOR

Giovanni Resta, May 10 2006

STATUS

approved

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Last modified November 22 10:59 EST 2019. Contains 329389 sequences. (Running on oeis4.)