Numerator of Sum_{k=1..n} 2^k/k.

Terms

a(0) =0a(1) =2a(2) =4a(3) =20a(4) =32a(5) =256a(6) =416a(7) =4832a(8) =8192a(9) =42496a(10) =74752a(11) =1467392a(12) =2650112a(13) =62836736a(14) =115552256a(15) =42790912a(16) =79691776a(17) =2535587840a(18) =4766040064a(19) =170851041280