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A239581
Number of primitive Pythagorean triangles (x, y, z) with legs x < y < 10^n.
2
1, 18, 179, 1788, 17861, 178600, 1786011, 17860355, 178603639, 1786036410, 17860362941
OFFSET
1,2
COMMENTS
A Pythagorean triangle is a right triangle with integer side lengths x, y, z forming a Pythagorean triple (x, y, z). It is called primitive, if gcd(x, y, z) = 1.
Because (x, y, z) is equivalent to (y, x, z), the total number of primitive Pythagorean triangles with legs x, y < 10^n is b(n) = 2*a(n) = 2, 36, 358, 3576, 35722, ...
LINKS
Eric Weisstein's World of Mathematics, Pythagorean Triangle.
Eric Weisstein's World of Mathematics, Pythagorean Triple.
EXAMPLE
a(1) = 1, because the only primitive Pythagorean triangle with x < y < 10 is [3, 4, 5].
KEYWORD
nonn,more
AUTHOR
Martin Renner, Mar 26 2014
EXTENSIONS
a(6)-a(11) from Giovanni Resta, Mar 27 2014
STATUS
approved