A305704 Numbers that are the semiperimeter of some triangle with integer sides and area.

6, 8, 9, 12, 15, 16, 18, 20, 21, 22, 24, 25, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 48, 49, 50, 52, 54, 55, 56, 57, 60, 63, 64, 65, 66, 68, 70, 72, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 93, 95, 96, 98, 99, 100, 102, 104, 105

Offset

1,1

Links

Peter Kagey, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Heronian Triangle

Formula

a(n) = A051518(n)/2.

Mathematica

hp[p_] := Catch@ Block[{c, q=p/2}, Do[c = p-a-b; If[IntegerQ@ Sqrt[q (q-a) (q-b) (q-c)], Throw@ True], {a, p/2-1}, {b, p/2-a+1, p/2-1}]; False]; Select[Range@ 105, hp[2 #] &] (* Giovanni Resta, Jun 14 2018 *)

Crossrefs

Cf. A051518.

Sequence in context: A030725 A195101 A337381 * A043720 A191980 A304412

Adjacent sequences: A305701 A305702 A305703 * A305705 A305706 A305707

Keyword

nonn

Author

Peter Kagey, Jun 08 2018

Status

approved