Define C(n) by the recursion C(0) = 2*i where i^2 = -1, C(n+1) = 1/(1 + C(n)), then a(n) = 2*(-1)^n/Im(C(n)) where Im(z) denotes the imaginary part of the complex number z.

A069959

Define C(n) by the recursion C(0) = 2*i where i^2 = -1, C(n+1) = 1/(1 + C(n)), then a(n) = 2*(-1)^n/Im(C(n)) where Im(z) denotes the imaginary part of the complex number z.

Terms

    a(0) =1a(1) =5a(2) =8a(3) =25a(4) =61a(5) =164a(6) =425a(7) =1117a(8) =2920a(9) =7649a(10) =20021a(11) =52420a(12) =137233a(13) =359285a(14) =940616a(15) =2462569a(16) =6447085a(17) =16878692a(18) =44188985a(19) =115688269a(20) =302875816a(21) =792939185a(22) =2075941733a(23) =5434886020a(24) =14228716321a(25) =37251262949a(26) =97525072520a(27) =255323954617a(28) =668446791325

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