-arctanh(log(cos(x))) = 1/2!*x^2+2/4!*x^4+46/6!*x^6+1112/8!*x^8...

A012006

-arctanh(log(cos(x))) = 1/2!*x^2+2/4!*x^4+46/6!*x^6+1112/8!*x^8...

Terms

    a(0) =1a(1) =2a(2) =46a(3) =1112a(4) =63376a(5) =4635872a(6) =523749136a(7) =76049858432

External references