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 A259686 #9 Jan 01 2021 04:28:05 %S A259686 1,3,1,17,1,3,1,3,5,1,5,7,7,3,1,1,5,11,1,15,5,7,1,1,1,1,1,7,1,9,15,1, %T A259686 1,1,1,5,9,7,17,1,97,7,799,11,49,17,1,3,1,1,63,1,1,55,161,3,1,1,1,1,1, %U A259686 161,7,1,1,1,1,7,3783,1,7,1697,21,319,21,911,3,1 %N A259686 Let m = A062695(n); a(n) is value of c in decomposition of m defined in Comments. %C A259686 Let m = A062695(n). Write m*y^2 = x^3 - x as m*square = A*B*(A-B)*(A+B) where A and B are the numerator and denominator of x. Then A, B, A-B, A+B have the form s*a^2, t*b^2, u*c^2, v*d^2 for some decomposition of m as s*t*u*v and some natural numbers a,b,c,d. These eight numbers are given in A259680-A259687. %H A259686 G. Kramarz, <a href="http://dx.doi.org/10.1007/BF01451411">All congruent numbers less than 2000</a>, Math. Annalen, 273 (1986), 337-340. %H A259686 G. Kramarz, <a href="/A003273/a003273.pdf">All congruent numbers less than 2000</a>, Math. Annalen, 273 (1986), 337-340. [Annotated, corrected, scanned copy] %Y A259686 Cf. A003273, A006991, A062695, A259680-A259687. %K A259686 nonn %O A259686 1,2 %A A259686 _N. J. A. Sloane_, Jul 04 2015 %E A259686 More terms from _Jinyuan Wang_, Jan 01 2021