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 A224773 #12 Feb 16 2025 08:33:19 %S A224773 7,13,15,19,21,23,25,27,31,33,35,37,39,43,45,47,49,53,55,57,59,61,63, %T A224773 67,69,71,73,75,77,79,81,83,85,87,89,91,93,95,97,99,101,103,105,107, %U A224773 109,111,113,115,117,119,121,123,125,127,129,131,133,135,137,139 %N A224773 One half of the even terms of A224771. %C A224773 2*a(n), n >= 1, gives all even numbers representable as a primitive sum of three distinct nonzero squares. %C A224773 The numbers a(n) are of interest in a problem related to integer solutions for the curvatures of the Descartes-Steiner circle theorem. %H A224773 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DescartesCircleTheorem.html">Descartes Circle Theorem</a>. %F A224773 a(n) is one half of the n-th even term of A224771. %e A224773 a(1) = 7 because the first even term of A224771 is 14 (m = 1). %e A224773 a(9) = 31 because 62 is the ninth even term of A224771 (m = 18). %Y A224773 Cf. A224771. %K A224773 nonn %O A224773 1,1 %A A224773 _Wolfdieter Lang_, Apr 19 2013