Denominator of average distance traveled by n-dimensional fly.

Terms

a(0) =1a(1) =3a(2) =4a(3) =15a(4) =8a(5) =35a(6) =64a(7) =315a(8) =128a(9) =693a(10) =512a(11) =3003a(12) =1024a(13) =6435a(14) =16384a(15) =109395a(16) =32768a(17) =230945a(18) =131072a(19) =969969a(20) =262144a(21) =2028117a(22) =2097152a(23) =16900975a(24) =4194304a(25) =35102025a(26) =16777216a(27) =145422675a(28) =33554432