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 A331241 #9 Jan 13 2020 22:31:15 %S A331241 3,12,25,27,48,75,100,108,112,147,162,169,192,225,240,243,289,300,363, %T A331241 400,405,432,448,507,588,625,648,675,676,768,841,867,891,900,960,972 %N A331241 Integer values that can be assumed by the squared radius of the circumcircle of a triangle with integer sides. %C A331241 Values of A331227(k) at positions k for which A331228(k) = 1. %F A331241 Squared radius of circumcircle of triangle with sides a, b, c: %F A331241 R^2 = (a*b*c)^2 / (16*s*(s - a)*(s - b)*(s - c)) with s = (a + b + c)/2. %e A331241 a(1) = 3, because the triangle with sides (3,3,3) is the first triangle for which R^2 has an integer value. %e A331241 a(2) = 12: (6,6,6), %e A331241 a(3) = 25: (6,8,10) scaled-up Pythagorean triangle (3,4,5), %e A331241 a(4) = 27: (9,9,9), %e A331241 a(5) = 48: (12,12,12), %e A331241 ... %e A331241 a(10) = 147: (9,15,21). %Y A331241 Cf. A331227, A331228. %K A331241 nonn,more %O A331241 1,1 %A A331241 _Hugo Pfoertner_, Jan 13 2020