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 A166930 #36 Jan 11 2025 20:42:43 %S A166930 2165017,15512114571284835412957, %T A166930 368440923990671763222767414151367493861848396861, %U A166930 29032470413228645503712143213832535500985227130245791625262982715784415755764157625 %N A166930 Positive integers m such that m^4 = a^2 + b^2 and a + b = c^2 for some positive coprime integers a, b, c. %C A166930 Square roots of the hypotenuses of Pythagorean triangles in which the hypotenuse and the sum of the legs are squares. In a letter to Mersenne in the year 1643, Fermat asserted that the smallest such triangle has the legs 4565486027761 and 1061652293520, and the hypotenuse a(1)^2 = 4687298610289. %C A166930 Subsequence of A166929 which allows a,b be nonzero. %C A166930 Values of m in coprime solutions to 2m^4 = c^4 + d^2 with d < c^2 (so that a,b = (c^2 +- d)/2). Corresponding values of c are given in A167438. %D A166930 W. Sierpinski. Pythagorean Triangles. Dover Publications, 2003, ISBN 0-486-43278-5. %H A166930 Gerry Martens, <a href="/A166930/b166930.txt">Table of n, a(n) for n = 1..13</a> %Y A166930 Cf. A166929, A167437, A167438. %K A166930 nonn %O A166930 1,1 %A A166930 _Max Alekseyev_, Oct 23 2009 %E A166930 Edited by _Max Alekseyev_, Nov 03 2009