Expansion of tan(x)*cos(tanh(x)).A009730Expansion of tan(x)*cos(tanh(x)).Terms a(0) =1a(1) =-1a(2) =41a(3) =-673a(4) =41425a(5) =-2148961a(6) =225227705a(7) =-23880701185External referencesoeis: A009730