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A305704 Numbers that are the semiperimeter of some triangle with integer sides and area. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified April 14 05:00 EDT 2021. Contains 342941 sequences. (Running on oeis4.)