Inverse Euler transform of central binomial coefficients A000984.

Terms

a(0) =1a(1) =2a(2) =3a(3) =10a(4) =30a(5) =102a(6) =335a(7) =1170a(8) =4080a(9) =14560a(10) =52377a(11) =190650a(12) =698870a(13) =2581110a(14) =9586395a(15) =35791358a(16) =134215680a(17) =505290270a(18) =1908866960a(19) =7233629130a(20) =27487764474a(21) =104715392730a(22) =399822314775