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 A130611 #9 Jan 07 2013 05:49:20
%S A130611 13,149,274,1705,19513,35890,66012,121415,755476,1389537,4700770
%N A130611 Tribonacci numbers A000073 which can be the hypotenuse of a Pythagorean triple.
%C A130611 The first 2 values are hypotenuses of primitive Pythagorean triples, A000073 INTERSECTION A020882: (5^2 + 12^2 = 13^2), (51^2 + 140^2 = 149^2). The other values listed have one or more nonprimitive solution: a(6) = 35890 has 13 solutions; a(8), a(9), a(10), a(11) have 4 solutions each.
%F A130611 A000073 INTERSECTION A009000. {c in A000073 such that there exist integers a, b with a^2 + b^2 = c^2}.
%e A130611 a(4) = 1705 because 1023^2 + 1364^2 = 1705^2, which is a nonprimitive Pythagorean triple 341*(3,4,5).
%Y A130611 Cf. A000073, A020882, A009000.
%K A130611 nonn
%O A130611 1,1
%A A130611 _Jonathan Vos Post_, Jun 17 2007