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.

This page as a plain text file.
%I A078259 #11 Jun 25 2025 19:27:36
%S A078259 10,100,200,10000,100000,10000000,1000000000,20000000000,
%T A078259 10000000000000,1000000000000000,100000000000000000,
%U A078259 10000000000000000000,40000000000000000000,100000000000000000000000,10000000000000000000000000,1000000000000000000000000000
%N A078259 a(n) = denominator(N), where N = 0.135..(2n-1) is the concatenation of the first n odd numbers after decimal point.
%p A078259 a:= n-> (t-> denom(t/10^length(t)))(parse(cat(2*i-1$i=1..n))):
%p A078259 seq(a(n), n=1..16);  # _Alois P. Heinz_, Jun 25 2025
%Y A078259 Cf. A019519, A031312.
%K A078259 base,frac,nonn
%O A078259 1,1
%A A078259 _Amarnath Murthy_, Nov 24 2002
%E A078259 Corrected and extended by _Sascha Kurz_, Jan 04 2003
%E A078259 a(4)-a(5) corrected and more terms from _Sean A. Irvine_, Jun 25 2025