A224931 Number of integer parallelograms with integer side lengths n = a >= b and integer diagonal lengths e >= f.

0, 0, 0, 1, 1, 0, 2, 1, 2, 2, 3, 3, 4, 3, 4, 6, 6, 4, 7, 5, 6, 9, 8, 9, 10, 9, 9, 9, 15, 9, 15, 12, 11, 15, 13, 12, 20, 18, 16, 15, 21, 17, 21, 18, 20, 21, 25, 20, 22, 23, 25, 24, 27, 22, 29, 26, 28, 31, 34, 26, 35, 32, 26, 33, 35, 30, 41, 33, 36, 34, 42, 35

Offset: 1

Author

Reiner Moewald, Apr 20 2013

Keywords

• nonn

Comments

It is easy to see that a < e < a + b and e^2 + f^2 = 2(a^2 + b^2).

Links

• Reiner Moewald, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A224932, A224933.