A119150 Triangular numbers composed of digits {1,8,9}.

1, 91, 1891, 8911, 188191, 889111, 899811, 998991, 1188111, 11899881, 88891111, 1918188891, 8888911111, 9998888991, 189889118191, 191819818191, 199198198891, 888889111111, 88888891111111, 8888888911111111, 888888889111111111, 88888888891111111111

Offset

1,2

Links

Table of n, a(n) for n=1..22.

Giovanni Resta, Tridigital Triangular Numbers

Formula

a(n) = A000217(A119151(n)). - Michel Marcus, Mar 24 2023

Crossrefs

Cf. A000217, A053915, A119151. See A119033 for a table of cross-references.

Sequence in context: A184462 A229518 A118706 * A008394 A332949 A221738

Adjacent sequences: A119147 A119148 A119149 * A119151 A119152 A119153

Keyword

nonn,base

Author

Giovanni Resta, May 10 2006

Extensions

a(21)-a(22) from Tyler Busby, Mar 24 2023

Status

approved