sec(tan(tan(x)))=1+1/2!*x^2+21/4!*x^4+1053/6!*x^6+96905/8!*x^8...
A012153
sec(tan(tan(x)))=1+1/2!*x^2+21/4!*x^4+1053/6!*x^6+96905/8!*x^8...
Terms
- a(0) =1a(1) =1a(2) =21a(3) =1053a(4) =96905a(5) =14216409a(6) =3045819741a(7) =897606889013
External references
- oeis: A012153