A024360 Number of primitive Pythagorean triangles with long leg n.

0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0

Offset

1,420

Comments

Consider primitive Pythagorean triangles (A^2 + B^2 = C^2, (A, B) = 1, A <= B); sequence gives number of times B takes value n.

Number of times n occurs in A020883.

Links

Ray Chandler, Table of n, a(n) for n = 1..10000

Ron Knott, Pythagorean Triples and Online Calculators

Formula

a(n) = A024361(n) - A024359(n). - Ray Chandler, Feb 03 2020

Mathematica

A[s_] := With[{s6 = StringPadLeft[ToString[s], 6, "0"]}, Cases[Import[ "https://oeis.org/A" <> s6 <> "/b" <> s6 <> ".txt", "Table"], {_, _}][[;; 10000, 2]]];
A@024361 - A@024359 (* Jean-François Alcover, Mar 27 2020 *)

Crossrefs

Cf. A020883, A024359, A024361.

Sequence in context: A160753 A328981 A369070 * A025456 A288314 A285963

Adjacent sequences: A024357 A024358 A024359 * A024361 A024362 A024363

Keyword

nonn

Author

David W. Wilson

Status

approved