A119071 Triangular numbers composed of digits {0,4,5}.

45, 55, 4005, 5050, 404550, 405450, 500500, 40405555, 40504500, 50005000, 454044045, 500054500, 4050045000, 4540044405, 5000050000, 405000450000, 455005054540, 500000500000, 40500004500000, 50000005000000, 50450455004040, 540550504445050, 4050000045000000

Offset

1,1

Links

Table of n, a(n) for n=1..23.

Giovanni Resta, Tridigital Triangular Numbers

Formula

a(n) = A000217(A119072(n)). - Michel Marcus, Mar 15 2023

Crossrefs

Cf. A000217, A058436, A119072. See A119033 for a table of cross-references.

Sequence in context: A037042 A119208 A068812 * A119158 A119204 A119206

Adjacent sequences: A119068 A119069 A119070 * A119072 A119073 A119074

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

a(21)-a(23) from Tyler Busby, Mar 14 2023

Status

approved