246695568861domain: NAppears in sequencesE.g.f.: exp(arctan(arctan(x))) = 1+x+1/2!*x^2-3/3!*x^3-15/4!*x^4+49/5!*x^5...at n=15A012203sinh(arctan(arctan(x)))=x-3/3!*x^3+49/5!*x^5-1859/7!*x^7+119617/9!*x^9...at n=7A012206