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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A223941 Areas of primitive Heron triangles with two rational triangle medians.

Original entry on oeis.org

420, 55440, 2042040, 23931600, 75698280, 142334216640, 1877686881840, 185643608470320, 2137147184560080
Offset: 1

Views

Author

Arkadiusz Wesolowski, Mar 29 2013

Keywords

Comments

All terms are divisible by 30.
It is not certain whether other values lie between those given. - Peter Luschny and Andrey Zabolotskiy, Apr 08 2024

Crossrefs

Cf. A181928.
A360537 is a subsequence.

Programs

  • Mathematica
    (*Brute-force search*)lst = {}; Do[s = (a + b + c)/2; d = Sqrt[s*(s - a)*(s - b)*(s - c)]; If[IntegerQ[d] && Divisible[d, 30] && d > 0, p = {{a, c, b}, {b, c, a}}; t = 0; Do[m = 1/2*Sqrt[2*p[[n, 1]]^2 + 2*p[[n, 2]]^2 - p[[n, 3]]^2]; If[MatchQ[m, _Rational] || IntegerQ[m], t++, Break[]], {n, 2}]; If[t == 2, AppendTo[lst, d]]], {a, 73}, {b, 51}, {c, 26}]; lst

Extensions

a(7)-a(9) from Hone (2024) added by Andrey Zabolotskiy, Apr 06 2024
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