A120891 Number of primitive Pythagorean triangles with odd leg 2n-1.

0, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 2, 2, 2, 1, 2, 1, 1, 4, 1, 1, 2, 1, 2, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 2, 2, 1, 4, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 2, 2, 1, 1, 4, 1, 1, 2, 2

Offset: 1

Author

Lekraj Beedassy, Jul 12 2006

Keywords

• nonn

Comments

Bisection of A024361.

Bisection of even-numbered terms of A024361 results in alternating zero terms; removing zeros gives A068068. - Ray Chandler, Feb 04 2020

Links

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

Crossrefs

Cf. A024361, A068068, A092523, A120890.

Formula

a(n)=2^(k-1), where k=A092523(n) for n > 1.

Extensions

a(1)=0 inserted by Ray Chandler, Feb 04 2020