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A119046 Numbers k such that the k-th triangular number contains only digits {0,1,8}. 2
1, 4, 46, 126, 141, 404, 466, 1541, 4004, 4195, 4666, 12658, 13266, 40004, 41995, 46666, 147024, 400004, 402760, 466666, 1272798, 1327266, 1332666, 4000004, 4666666, 40000004, 46666666, 133272666, 133326666, 148329375, 400000004 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..31.

G. Resta, Tridigital Triangular Numbers

MATHEMATICA

Select[Range[2 10^7], Complement[IntegerDigits[Binomial[# + 1, 2]], {0, 1, 8}] == {} &] (* Vincenzo Librandi, Dec 25 2015 *)

PROG

(MAGMA) [n: n in [1..4*10^6] | Set(Intseq(Binomial(n+1, 2))) subset [0, 1, 8]]; // Vincenzo Librandi, Dec 25 2015

CROSSREFS

Cf. A000217, A119045. See A119034 for a table of cross-references.

Sequence in context: A134110 A176312 A309450 * A273776 A131540 A218997

Adjacent sequences:  A119043 A119044 A119045 * A119047 A119048 A119049

KEYWORD

nonn,base

AUTHOR

Giovanni Resta, May 10 2006

STATUS

approved

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Last modified January 20 06:12 EST 2022. Contains 350467 sequences. (Running on oeis4.)