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A020890 Ordered set of (b + c - a)/2 as (a,b,c) runs through all primitive Pythagorean triples with a < b < c. 5

%I

%S 3,10,12,15,21,30,35,36,40,44,52,55,56,63,65,70,77,78,85,90,99,102,

%T 105,114,117,119,126,132,133,136,143,152,154,161,165,168,171,176,182,

%U 184,187,195,198,200,207,208,210,216,221,225,230,234,240,247,253,255,260,261,270

%N Ordered set of (b + c - a)/2 as (a,b,c) runs through all primitive Pythagorean triples with a < b < c.

%C From _Bernard Schott_, May 06 2021: (Start)

%C Also, ordered sides b of primitive triples (a, b, c) for integer-sided triangles where side a is the harmonic mean of the 2 other sides b and c, i.e., 2/a = 1/b + 1/c with b < a < c (A343892).

%C The first term appearing twice is 330 = a(71) = a(72). (End)

%H Ray Chandler, <a href="/A020890/b020890.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A020889(n)/2.

%Y Cf. A020889.

%Y Cf. Triangles with 2/a = 1/b + 1/c: A343891 (triples), A020883 (side a), A343892 (side b), A343893 (side c), A343894 (perimeter).

%K nonn

%O 1,1

%A _Clark Kimberling_

%E Offset corrected to 1 by _Ray Chandler_, Jan 23 2020

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Last modified June 23 21:09 EDT 2021. Contains 345402 sequences. (Running on oeis4.)