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A106499 Ordered perimeter of primitive integer-sided triangle one of whose angles is twice another. 12

%I #10 Mar 06 2020 08:11:35

%S 15,28,40,45,66,77,84,91,104,120,126,144,153,170,187,190,198,209,220,

%T 228,231,260,273,276,286,299,312,322,325,345,350,378,390,400,420,432,

%U 435,442,459,464,476,493,496,510,522,527,544,551,558,561,570,589,608

%N Ordered perimeter of primitive integer-sided triangle one of whose angles is twice another.

%C For corresponding values of r and s, see A106500 and A106501.

%C The sides of the primitive triangle are given by the triple (r*s,s^2 - r^2,r^2).

%H Jean-François Alcover, <a href="/A106499/b106499.txt">Table of n, a(n) for n = 1..869</a>

%F a(n)=s*(r+s), where r<s<2r and (r, s)=1.

%t s[p_] := Solve[1 < r < s < 2r && p == r s + s^2 && GCD[r, s] == 1, {r, s}, Integers];

%t 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 *)

%Y Cf. A106500-A106506, A106410, A106420, A106430.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, May 04 2005

%E Extended by _Ray Chandler_, May 09 2005

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Last modified March 28 12:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)