A053963 -id:A053963 - cp's OEIS frontend

A119216 Triangular numbers composed of digits {4,7,8}.

78, 8778, 448878, 887778, 7478778, 88877778, 8888777778, 44847878778, 747488474778, 888887777778, 88888877777778, 8888888777777778, 888888887777777778, 7778777484477877878, 88888888877777777778, 7444484774887874784778, 8888888888777777777778

Offset: 1

Giovanni Resta, May 10 2006

Giovanni Resta, Tridigital Triangular Numbers.

Cf. A000217, A053963, A119217. See A119033 for a table of cross-references.

Table[Select[FromDigits/@Tuples[{4,7,8},n],OddQ[Sqrt[8#+1]]&],{n,20}]//Flatten (* The program will take a long time to run. *) (* Harvey P. Dale, Oct 15 2017 *)

a(n) = A000217(A119217(n)). - Tyler Busby, Mar 26 2023

a(16)-a(17) from Tyler Busby, Mar 26 2023

A053962 Numbers k such that k^2 contains only digits {4,7,8}.

Original entry on oeis.org

2, 22, 28, 88, 86478, 94227622, 9208064263934568938, 22019193553462506122, 6984617991328143315228383028

Offset: 1

Patrick De Geest, Mar 15 2000

Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences
H. Mishima Squares consisted of 3 different digits [From _Max Alekseyev_, Mar 10 2009]

Cf. A053963.

Two more terms from Mishima's page added by Max Alekseyev, Mar 10 2009

a(9) from Zhao Hui Du, Mar 09 2024

cp's OEIS Frontend

A119216 Triangular numbers composed of digits {4,7,8}.

Views

Author

Keywords

Links

Crossrefs

Programs

Mathematica

Formula