A333945 Perimeters of integer-sided triangles with integer inradius.

12, 24, 30, 32, 36, 40, 42, 44, 48, 54, 56, 60, 64, 66, 68, 70, 72, 76, 78, 80, 84, 88, 90, 96, 104, 108, 110, 112, 114, 120, 126, 128, 130, 132, 136, 140, 144, 150, 152, 154, 156, 160, 162, 164, 168, 170, 172, 174, 176, 180, 182, 186, 190, 192, 198, 200, 204, 208, 210

Offset

1,1

Links

Table of n, a(n) for n=1..59.

Eric Weisstein's World of Mathematics, Incircle

Wikipedia, Incircle and excircles of a triangle

Wikipedia, Integer Triangle

Mathematica

Flatten[Table[If[Sum[Sum[(1 - Ceiling[Sqrt[(n/2) (n/2 - i) (n/2 - k) (n/2 - (n - i - k))]/(n/2)] + Floor[Sqrt[(n/2) (n/2 - i) (n/2 - k) (n/2 - (n - i - k))]/(n/2)]) Sign[Floor[(i + k)/(n - i - k + 1)]], {i, k, Floor[(n - k)/2]}], {k, Floor[n/3]}] > 0, n, {}], {n, 100}]]

Crossrefs

Cf. A005044, A333946 (prime inradius).

Sequence in context: A126935 A333918 A334665 * A335146 A365008 A182225

Adjacent sequences: A333942 A333943 A333944 * A333946 A333947 A333948

Keyword

nonn

Author

Wesley Ivan Hurt, Apr 11 2020

Status

approved