The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A119139 Numbers k such that the k-th triangular number contains only digits {1,5,9}. 2

%I #8 Jul 13 2021 07:28:36

%S 1,5,10,13,34,101,109,138,1738,10114,19794,1011090,1019010,1054130,

%T 1091010,34406858,178858133,565606858,4289521091010,55841058721258

%N Numbers k such that the k-th triangular number contains only digits {1,5,9}.

%C Next term exceeds 1.4*10^16.

%H G. Resta, <a href="http://www.numbersaplenty.com/tr/tr159.html">Tridigital Triangular Numbers</a>

%Y Cf. A000217, A119138. See A119034 for a table of cross-references.

%K nonn,base,more

%O 1,2

%A _Giovanni Resta_, May 10 2006

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 24 06:28 EDT 2024. Contains 372772 sequences. (Running on oeis4.)