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.
%I A180429 #33 Feb 16 2025 08:33:13 %S A180429 2,40,463,5081,53722,557687,5730883,58527612,595228791,6035604901, %T A180429 61067111413,616833883887,6222429697992,62704089037652, %U A180429 631334954674157,6352077572091621 %N A180429 The number of n-digit numbers requiring 3 nonzero squares in their representation as sum of squares. %C A180429 A049415(n) + A180426(n) + a(n) + A180347(n) = A052268(n) %H A180429 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LagrangesFour-SquareTheorem.html">Lagrange's Four-Square Theorem</a>, <a href="https://mathworld.wolfram.com/SumofSquaresFunction.html">Sum of Squares Function</a>. %F A180429 a(n) = A180425(n)-A180425(n-1) for n>1. %Y A180429 Cf. A000419, A180425. %K A180429 nonn,more,base %O A180429 1,1 %A A180429 _Martin Renner_, Jan 19 2011 %E A180429 a(6) from _Lars Blomberg_, Jun 29 2011 %E A180429 a(7)-a(10) from _Donovan Johnson_, Jul 01 2011 %E A180429 a(10) corrected and a(11)-a(16) added by _Hiroaki Yamanouchi_, Aug 30 2014