A056138 Number of ways in which n can be the shorter leg (shortest side) of an integer-sided right triangle.

0, 0, 1, 0, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 3, 2, 1, 2, 1, 3, 3, 1, 1, 4, 2, 1, 3, 3, 1, 3, 1, 3, 4, 1, 3, 5, 1, 1, 4, 5, 1, 3, 1, 3, 5, 1, 1, 7, 2, 2, 4, 3, 1, 3, 3, 5, 4, 1, 1, 9, 1, 1, 5, 4, 4, 4, 1, 3, 4, 3, 1

Offset

1,9

Links

Table of n, a(n) for n=1..71.

Formula

a(n) = A046079(n) - A056137(n) = A046081(n) - A046080(n) - A056137(n).

Prog

(PARI) a(n)=my(b); sum(c=n+2, n^2\2+1, issquare(c^2-n^2, &b) && n<b) \\ Charles R Greathouse IV, Jul 07 2013

Crossrefs

Cf. A009004, A055525, A055527.

Sequence in context: A145574 A182579 A290737 * A067594 A089533 A284312

Adjacent sequences: A056135 A056136 A056137 * A056139 A056140 A056141

Keyword

nonn

Author

Henry Bottomley, Jun 15 2000

Status

approved