Numerator of sum( k!/2^k, k=1..n ).

Terms

a(0) =0a(1) =1a(2) =1a(3) =7a(4) =13a(5) =7a(6) =73a(7) =461a(8) =1721a(9) =7391a(10) =35741a(11) =95833a(12) =140902a(13) =7208291a(14) =6221977a(15) =738064507a(16) =5846167507a(17) =49265043007a(18) =440034922507