A119130 Triangular numbers composed of digits {1,4,9}.

1, 91, 49141, 144991, 94414411, 941194191, 1194944941, 491919414441, 9999119991411411, 4149449911949149941, 11144994144991949991, 191444491991911949911, 144949944191119411441191, 9449441991199141999494149499499111914141

Offset

1,2

Links

Table of n, a(n) for n=1..14.

Giovanni Resta, Tridigital Triangular Numbers.

Formula

a(n) = A000217(A119131(n)). - Tyler Busby, Mar 31 2023

Crossrefs

Cf. A000217, A006716, A119131. See A119033 for a table of cross-references.

Sequence in context: A348088 A157802 A214110 * A195217 A352755 A116677

Adjacent sequences: A119127 A119128 A119129 * A119131 A119132 A119133

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

a(14) from Max Alekseyev, Aug 15 2013

Status

approved