G.f.: Sum_{n>=0} Product_{k=1..n} tan(k*arctan(x)).

A177381

G.f.: Sum_{n>=0} Product_{k=1..n} tan(k*arctan(x)).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =26a(5) =142a(6) =930a(7) =7110a(8) =62138a(9) =610958a(10) =6674370a(11) =80201222a(12) =1051277530a(13) =14927729678a(14) =228262465634

External references