3807514624

Appears in sequences

• Number of alternating permutations of order n.at n=15A001250
• E.g.f.: -log(cos(x)*cos(x)) (even powers only).at n=8A012509
• -log(cosh(x)*cos(x))=-4/4!*x^4-544/8!*x^8-707584/12!*x^12...at n=3A012770
• An Euler triangle.at n=38A117414
• E.g.f. (x*tan(x)-x^2)/8 (even powers only).at n=8A117415
• Number of arrays of length n that are sums of 2 consecutive elements of length n+1 permutations of 0..n, and no two consecutive rises or falls in the latter permutation.at n=13A229712
• Twice the Euler or up/down numbers A000111.at n=15A260786
• Expansion of e.g.f.: sec(x) + 2*tan(x).at n=15A309845
• a(n) = E2_{n}(0) with E2_{n} the polynomials defined in A326480.at n=15A326481