1,1

Primitive Pythagorean hypotenuses (A004431) are of the form m^2+n^2, m>n>0.

a(2)=29 because there are 29 primitive Pythagorean hypotenuses which are {5, 10, 13, 17, 20, 25, 26, 29, 34, 37, 40, 41, 45, 50, 52, 53, 58, 61, 65, 68, 73, 74, 80, 82, 85, 89, 90, 97, 100}

hyp = Union[ Flatten[ Table[ m^2 + n^2, {n, 2, 100000}, {m, n - 1}]]]; Table[ Length[ Select[ hyp, #<=10^n &]], {n, 8}]

Cf. A004431.

Sequence in context: A036939 A124301 A077023 this_sequence A160952 A088615 A091716

Adjacent sequences: A101747 A101748 A101749 this_sequence A101751 A101752 A101753

nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 09 2004