E.g.f.: Sum_{n>=0} tan(2^n*x)^n/n!.A168404E.g.f.: Sum_{n>=0} tan(2^n*x)^n/n!.Terms a(0) =1a(1) =2a(2) =16a(3) =528a(4) =67584a(5) =34210304a(6) =69391122432External referencesoeis: A168404