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%I #17 Jul 02 2021 16:45:19
%S 0,3,14,33,62,101,148,207,276,353,448,547,662,785,920,1067,1230,1397,
%T 1586,1773,1986,2205,2436,2671,2940,3207,3494,3787,4096,4399,4764,
%U 5095,5458,5825,6208,6603,7050,7453,7880,8331,8826,9277,9800,10279,10808
%N Number of right triangles with nonnegative integer coordinates less than or equal to n and one corner at the origin.
%H Project Euler, <a href="https://projecteuler.net/problem=91">Problem 91: Right triangles with integer coordinates</a>.
%o (PARI) a(n)=3*n^2+sum(a=1, n, sum(b = 1, n, 2*min(b*gcd(a, b)\a, (n - a)*gcd(a, b)\b) ) ) \\ _Yurii Ivanov_, Jun 25 2021
%K nonn
%O 0,2
%A Emlyn Corrin (emlyn(AT)corrin.name), Jan 21 2009
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