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 A156679 Consider primitive Pythagorean triangles (A^2 + B^2 = C^2, gcd (A, B) = 1, A < B
 5, 13, 25, 17, 41, 61, 37, 85, 113, 65, 145, 181, 29, 101, 221, 265, 145, 313, 365, 53, 197, 421, 481, 257, 65, 545, 613, 85, 325, 685, 89, 761, 401, 841, 925, 125, 485, 1013, 1105, 73, 577, 1201, 149, 1301, 173, 677, 1405, 1513, 785, 185, 1625, 1741, 109, 229 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The ordered sequence of A values is A020884(n) and the ordered sequence of C values is A020882(n) (allowing repetitions) and A008846(n) (excluding repetitions). REFERENCES Beiler, Albert H.: Recreations In The Theory Of Numbers, Chapter XIV, The Eternal Triangle, Dover Publications Inc., New York, 1964, pp. 104-134. Sierpinski, W.; Pythagorean Triangles, Dover Publications, Inc., Mineola, New York, 2003. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..1000 EXAMPLE As the first four primitive Pythagorean triples (ordered by increasing A) are (3,4,5), (5,12,13), (7,24,25) and (8,15,17), then a(1)=5, a(2)=13, a(3)=25 and a(4)=17. MATHEMATICA PrimitivePythagoreanTriplets[n_]:=Module[{t={{3, 4, 5}}, i=4, j=5}, While[i uu `div` 2        = f (u + 1) (u + 2)          | gcd u v > 1 || w == 0 = f u (v + 2)          | otherwise             = w : f u (v + 2)          where uu = u ^ 2; w = a037213 (uu + v ^ 2) -- Reinhard Zumkeller, Nov 09 2012 CROSSREFS Cf. A020884, A020882, A008846, A156678, A156682. Cf. A037213. Sequence in context: A271937 A121511 A283750 * A344813 A190618 A309585 Adjacent sequences:  A156676 A156677 A156678 * A156680 A156681 A156682 KEYWORD easy,nice,nonn AUTHOR Ant King, Feb 15 2009 STATUS approved

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Last modified June 21 04:47 EDT 2021. Contains 345355 sequences. (Running on oeis4.)