Computing the n-th Euler zigzag number An

A2n = Sn if n ≥ 0;
A2n-1 = Tn if n ≥ 1.

Here Sn is the nth secant number and Tn is the nth tangent number.

See Euler zigzag numbers and OEIS A000111.

Enter n (1 ≤ n ≤ 1000):

Last modified 26th February 2023
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