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(MAGMAMagma) [((2*n-1)*(2*n-1-(-1)^n))^2/4: n in [1..30]]; // Vincenzo Librandi, Mar 23 2012
From Amiram Eldar, Mar 06 2022: (Start)
Sum_{n>=0} 1/a(n) = (3*Pi-8)*Pi/4.
Sum_{n>=0} (-1)^n/a(n) = 4*(G - log(2)), where G is Catalan's constant (A006752). (End)
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G.f.: x*(1 + 8*x + 212*x^2 + 184*x^3 + 726*x^4 + 184*x^5 + 212*x^6 + 8*x^7 + x^8)/((1 - x)^5*(1 + x)^4).
E.g.f.: (1 + x + 5*x^2 + 20*x^3 + 4*x^4)*cosh(x) - x*(1 - 17*x - 12*x^2 - 4*x^3)* sinh(x) - 1. (End)
(Scala) ((1 to 78).scanLeft(0)(_ + _)).filter(_ % 2 == 1).map(n => n * n) // Alonso del Arte, Jul 24 2019
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