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 A024359 Consider primitive Pythagorean triangles (A^2 + B^2 = C^2, (A, B) = 1, A <= B); sequence gives number of times A takes value n. 5
 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 2, 1, 0, 1, 1, 1, 0, 1, 2, 1, 0, 1, 1, 2, 0, 1, 2, 1, 0, 2, 1, 1, 0, 1, 2, 1, 0, 1, 2, 1, 0, 2, 2, 1, 0, 1, 1, 2, 0, 1, 3, 1, 0, 1, 1, 2, 0, 1, 2, 2, 0, 1, 1, 1, 0, 2, 2, 1, 0, 1, 1, 1, 0, 1, 3, 2, 0, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,20 COMMENTS Number of times n occurs in A020884. a(A139544(n)) = 0; a(A024352(n)) > 0. - Reinhard Zumkeller, Nov 09 2012 LINKS T. D. Noe, Table of n, a(n) for n = 1..10000 Ron Knott, Pythagorean Triples and Online Calculators MATHEMATICA solns[a_] := Module[{b, c, soln}, soln = Reduce[a^2 + b^2 == c^2 && a < b && c > 0 && GCD[a, b, c] == 1, {b, c}, Integers]; If[soln === False, 0, If[soln[[1, 1]] === b, 1, Length[soln]]]]; Table[solns[n], {n, 100}] PROG (Haskell) a024359_list = f 0 1 a020884_list where    f c u vs'@(v:vs) | u == v = f (c + 1) u vs                     | u /= v = c : f 0 (u + 1) vs' -- Reinhard Zumkeller, Nov 09 2012 (PARI) nppt(a) = {   my(s=0, b, c, d, g);   fordiv(a^2, d,     g=a^2\d;     if(d<=g && (d+g)%2==0,       c=(d+g)\2; b=g-c;       if(a

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Last modified September 18 13:45 EDT 2018. Contains 315130 sequences. (Running on oeis4.)