A106420 Length of side opposite the greater of the two angles, one being the double of the other, of a primitive integer-sided triangle, sorted on perimeter (A106499).

6, 12, 15, 20, 30, 28, 35, 42, 40, 56, 45, 63, 72, 70, 66, 90, 77, 88, 99, 84, 110, 91, 104, 132, 117, 130, 143, 126, 156, 120, 154, 182, 165, 144, 195, 176, 210, 153, 170, 208, 187, 204, 240, 221, 198, 238, 255, 190, 234, 272, 209, 228, 247, 220, 266, 306, 285

Offset

1,1

Links

Table of n, a(n) for n=1..57.

Formula

a(n) = A106500(n) * A106501(n).

Mathematica

sol[p_] := Solve[1 < r < s < 2 r && p == r s + s^2 && GCD[r, s] == 1, {r, s}, Integers];
Reap[For[p = 1, p <= 1000, p++, sp = sol[p]; If[sp =!= {}, Print[r s /. sp[[1]]]; Sow[r s /. sp[[1]]]]]][[2, 1]] (* Jean-François Alcover, Mar 07 2020 *)

Crossrefs

Cf. A106499-A106506, A106410, A106430.

Sequence in context: A063931 A001283 A106430 * A308611 A315619 A300479

Adjacent sequences: A106417 A106418 A106419 * A106421 A106422 A106423

Keyword

nonn

Author

Lekraj Beedassy and Ray Chandler, May 09 2005

Status

approved