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A010814
Perimeters of integer-sided right triangles.
37
12, 24, 30, 36, 40, 48, 56, 60, 70, 72, 80, 84, 90, 96, 108, 112, 120, 126, 132, 140, 144, 150, 154, 156, 160, 168, 176, 180, 182, 192, 198, 200, 204, 208, 210, 216, 220, 224, 228, 234, 240, 252, 260, 264, 270, 276, 280, 286, 288, 300, 306, 308, 312, 320, 324
OFFSET
1,1
COMMENTS
A number k is in this sequence iff k is a multiple of some term in A024364.
MAPLE
isA010814 := proc(an) local a::integer, b::integer, c::integer ; for c from 1 to floor(an/2) do for a from floor(c/sqrt(2)) to c-1 do if issqr(c^2-a^2) then b := sqrt(c^2-a^2) ; if a+b+c = an then RETURN(true) ; fi ; fi ; od ; od : RETURN(false) ; end : for n from 3 to 400 do if isA010814(n) then printf("%d, ", n) ; fi ; od ; # R. J. Mathar, Jun 08 2006
MATHEMATICA
lst={}; Do[Do[If[IntegerQ[c=Sqrt[a^2+b^2]], AppendTo[lst, a+b+c]], {b, a-1, Floor[Sqrt[a]], -1}], {a, 4, 4*5!}]; Take[Union@lst, 100] (* Vladimir Joseph Stephan Orlovsky, Nov 23 2010 *)
q[n_] := EvenQ[n] && Module[{d = Divisors[n/2]}, AnyTrue[Range[3, Length[d]], d[[#]] < 2 * d[[#-1]] &]]; Select[Range[350], q] (* Amiram Eldar, Oct 19 2024 *)
CROSSREFS
Twice A005279.
Cf. A024364.
Sequence in context: A289484 A027854 A009096 * A334760 A098714 A334758
KEYWORD
nonn,easy
AUTHOR
Ben Manvel (manvel(AT)lagrange.math.colostate.edu)
EXTENSIONS
More terms from Ray Chandler, Mar 13 2004
STATUS
approved