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A106499 Ordered perimeter of primitive integer-sided triangle one of whose angles is twice another. 12
15, 28, 40, 45, 66, 77, 84, 91, 104, 120, 126, 144, 153, 170, 187, 190, 198, 209, 220, 228, 231, 260, 273, 276, 286, 299, 312, 322, 325, 345, 350, 378, 390, 400, 420, 432, 435, 442, 459, 464, 476, 493, 496, 510, 522, 527, 544, 551, 558, 561, 570, 589, 608 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
For corresponding values of r and s, see A106500 and A106501.
The sides of the primitive triangle are given by the triple (r*s,s^2 - r^2,r^2).
LINKS
Jean-François Alcover, Table of n, a(n) for n = 1..869
FORMULA
a(n)=s*(r+s), where r<s<2r and (r, s)=1.
MATHEMATICA
s[p_] := Solve[1 < r < s < 2r && p == r s + s^2 && GCD[r, s] == 1, {r, s}, Integers];
Reap[For[p = 1, p <= 10000, p++, sp = s[p]; If[sp =!= {}, Sow[p]; Print[p, " ", {r s, s^2 - r^2, r^2} /. sp[[1]]]]]][[2, 1]] (* Jean-François Alcover, Mar 06 2020 *)
CROSSREFS
Sequence in context: A099808 A291054 A134621 * A043108 A045192 A039285
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, May 04 2005
EXTENSIONS
Extended by Ray Chandler, May 09 2005
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)