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.

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A375474 Numbers k such that k is the area of a rational isosceles triangle.

Original entry on oeis.org

3, 7, 10, 11, 12, 14, 15, 17, 19, 23, 26, 27, 28, 30, 31, 35, 39, 40, 42, 43, 44, 46, 47, 48, 51, 55, 56, 58, 59, 60, 62, 63, 67, 68, 69, 71, 74, 75, 76, 77, 78, 79, 82, 83, 87, 90, 91, 92, 94, 95, 97, 99, 103, 104, 105, 106, 107, 108, 110, 111, 112, 113, 115, 119, 120, 122, 123
Offset: 1

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Author

Frank M Jackson, Aug 17 2024

Keywords

Comments

All the integer areas of rational isosceles triangles can be obtained by multiplying a squarefree area of a rational isosceles triangle A375017 by a positive square number A000290.

Examples

			12 is the area of an isosceles triangle with sides (5, 5, 6).
40 is the area of an isosceles triangle with sides (12, 82/3, 82/3).
		

Crossrefs

Programs

  • Mathematica
    lst=Last/@ReadList["https://oeis.org/A375017/b375017.txt", {Number, Number}]; dmax=75; Select[(Sort@Flatten@Table[Table[lst[[n]]*d^2, {d, 1, dmax}], {n, 1, Length@lst}]), #<=140 &]
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