login
A056138
Number of ways in which n can be the shorter leg (shortest side) of an integer-sided right triangle.
1
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
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
KEYWORD
nonn
AUTHOR
Henry Bottomley, Jun 15 2000
STATUS
approved