a(n) = floor(Product_{k=1..n} (Sum_{j=1..k} 1/j)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =32a(6) =83a(7) =225a(8) =638a(9) =1871a(10) =5651a(11) =17537a(12) =55772a(13) =181348a(14) =601754a(15) =2034368a(16) =6997316a(17) =24456376a(18) =86764857a(19) =312157366a(20) =1137925574a(21) =4199870789a(22) =15683541837a(23) =59220398058a(24) =225982562259a(25) =871031643495