A309425 Difference x-y of generator pairs (x,y) {x and y coprime and not both odd, x > y} of primitive Pythagorean triangles, sorted by x and y (for same x).

1, 1, 3, 1, 3, 1, 5, 1, 5, 3, 1, 7, 5, 3, 1, 7, 5, 1, 9, 7, 3, 1, 9, 7, 5, 3, 1, 11, 7, 5, 1, 11, 9, 7, 5, 3, 1, 13, 11, 9, 5, 3, 1, 13, 11, 7, 1, 15, 13, 11, 9, 7, 5, 3, 1, 15, 13, 11, 9, 7, 5, 3, 1, 17, 13, 11, 7, 5, 1, 17, 15, 13, 11, 9, 7, 5, 3, 1, 19, 17, 13, 11, 9, 7, 3, 1

Offset: 1

Author

Rui Lin, Jul 31 2019

Keywords

• nonn

Comments

This sequence is based on x and y (for same x) in increasing order, directly mapping to A094192 and A094193, while A126637 is sorted by the sum x+y.

Given any two of the four sequences below, primitive Pythagorean triangles can be generated.

A094192: the bigger one in generator pairs;

A094193: the smaller one in generator pairs;

A309424: the sum of generator pairs;

A309425: the difference of generator pairs.

Crossrefs

Cf. A094192, A094193, A126637, A309424.

Formula

a(n) = A094192(n) - A094193(n).