cosh(arcsin(tan(x)))=1+1/2!*x^2+13/4!*x^4+421/6!*x^6+26713/8!*x^8...

A012084

cosh(arcsin(tan(x)))=1+1/2!*x^2+13/4!*x^4+421/6!*x^6+26713/8!*x^8...

Terms

    a(0) =1a(1) =1a(2) =13a(3) =421a(4) =26713a(5) =2871241a(6) =473357413a(7) =111506036461

External references