[ exp(13/16)*n! ].

Terms

a(0) =2a(1) =4a(2) =13a(3) =54a(4) =270a(5) =1622a(6) =11357a(7) =90862a(8) =817762a(9) =8177627a(10) =89953897a(11) =1079446768a(12) =14032807993a(13) =196459311909