cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A078259 a(n) = denominator(N), where N = 0.135..(2n-1) is the concatenation of the first n odd numbers after decimal point.

Original entry on oeis.org

10, 100, 200, 10000, 100000, 10000000, 1000000000, 20000000000, 10000000000000, 1000000000000000, 100000000000000000, 10000000000000000000, 40000000000000000000, 100000000000000000000000, 10000000000000000000000000, 1000000000000000000000000000
Offset: 1

Views

Author

Amarnath Murthy, Nov 24 2002

Keywords

Crossrefs

Programs

  • Maple
    a:= n-> (t-> denom(t/10^length(t)))(parse(cat(2*i-1$i=1..n))):
    seq(a(n), n=1..16);  # Alois P. Heinz, Jun 25 2025

Extensions

Corrected and extended by Sascha Kurz, Jan 04 2003
a(4)-a(5) corrected and more terms from Sean A. Irvine, Jun 25 2025