cp's OEIS Frontend

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.

A034025 Both primitively and imprimitively represented by x^2+y^2.

Original entry on oeis.org

25, 50, 125, 169, 250, 289, 325, 338, 425, 578, 625, 650, 725, 841, 845, 850, 925, 1025, 1250, 1325, 1369, 1445, 1450, 1525, 1625, 1681, 1682, 1690, 1825, 1850, 2050, 2125, 2197, 2225, 2425, 2525, 2650, 2725, 2738, 2809, 2825, 2873, 2890
Offset: 0

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  • Mathematica
    okQ[n_] := (xy = {x, y} /. {ToRules[Reduce[n == x^2 + y^2, {x, y}, Integers]]}; cnt = Count[xy, {x_, y_} /; GCD[x, y] == 1]; Length[xy] > cnt > 0); Reap[For[n = 1, n <= 3000, n++, If[okQ[n], Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, Jan 25 2013 *)