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 A081962 Ordered semiperimeters of primitive Pythagorean triangles with an even short leg (or an odd long leg). 1
 20, 35, 42, 63, 72, 88, 99, 110, 130, 143, 156, 165, 195, 210, 221, 238, 255, 266, 272, 285, 304, 323, 336, 342, 357, 391, 399, 414, 420, 437, 450, 460, 475, 483, 506, 525, 540, 550, 575, 594, 600, 609, 621, 638, 667, 675, 682, 696, 702, 713, 725, 744, 754 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS If m and n are the generators of the primitive Pythagorean triples (PPT) with m>n, GCD(m,n)=1 and (m+n) odd then the odd leg is m^2-n^2 and the even leg is 2m*n. Therefore the even leg is shortest if 2m*n(1+sqrt(2))*n. Also this is a sequence of numbers whose square is the semiperimeter of a PPT. - Frank M Jackson, Oct 10 2014 LINKS Ray Chandler, Table of n, a(n) for n = 1..10000 (first 1621 terms from Vincenzo Librandi) MATHEMATICA lst1 = {}; Do[If[GCD[m, n]==1&&m(Sqrt[2]+1)

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Last modified December 2 09:52 EST 2020. Contains 338876 sequences. (Running on oeis4.)