Number of terms in n-th derivative of a function composed with itself 5 times.

Terms

a(0) =1a(1) =1a(2) =5a(3) =15a(4) =45a(5) =110a(6) =271a(7) =599a(8) =1309a(9) =2690a(10) =5436a(11) =10545a(12) =20148a(13) =37341a(14) =68223a(15) =121878a(16) =214846a(17) =371993a(18) =636570a(19) =1073325a(20) =1790721a(21) =2950922a(22) =4816603a(23) =7778937a(24) =12455988a(25) =19761148a(26) =31108121a(27) =48572686a(28) =75307513a(29) =115909727