Number of distinct values taken by 9^9^...^9 (with n 9's and parentheses inserted in all possible ways).

A145549

Number of distinct values taken by 9^9^...^9 (with n 9's and parentheses inserted in all possible ways).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =20a(6) =48a(7) =115a(8) =286a(9) =719a(10) =1842a(11) =4766a(12) =12485a(13) =32969a(14) =87795a(15) =235326a(16) =634664a(17) =1720573a(18) =4686829a(19) =12820504a(20) =35204254a(21) =97001655a(22) =268120807a(23) =743236814a(24) =2065709551a(25) =5755253457

External references