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.

A181643 a(n) is the smallest value such that a(n)*[a(n)+n]*[a(n)+n+n]=y^2 is a perfect square.

This page as a plain text file.
%I A181643 #5 Jul 22 2025 08:42:10
%S A181643 0,0,0,0,40,6,18,0,0,0,0,0,0,4,10,0,0,0,0,5,7,0,0,1,0,0,0,72,0,15,0,0,
%T A181643 0,128,0,0,0,0,936,0,800,0,0,0,360,196,0,0,0,0,0,0,0,54
%N A181643 a(n) is the smallest value such that a(n)*[a(n)+n]*[a(n)+n+n]=y^2 is a perfect square.
%C A181643 For a given n there is more than one solution.
%e A181643 a(5)=40 since 40*(40+5)*(40+5+5)=40*45*50=90000=300^2
%Y A181643 Cf. A115878, A181646.
%K A181643 nonn
%O A181643 1,5
%A A181643 _Carmine Suriano_, Nov 03 2010, corrected Nov 10 2010