A145546 Number of distinct values taken by 6^6^...^6 (with n 6's and parentheses inserted in all possible ways).

1, 1, 2, 4, 9, 20, 48, 115, 286, 718, 1838, 4750, 12431, 32790, 87225, 233534, 629123, 1703586, 4635181, 12664335, 34734322, 95592704, 263909594

Offset: 1

Author

Jon E. Schoenfield, Oct 13 2008

Keywords

• more
• nonn

Links

• R. K. Guy and J. L. Selfridge, The nesting and roosting habits of the laddered parenthesis, Amer. Math. Monthly 80 (8) (1973), 868-876.
• Index entries for sequences related to parenthesizing

Crossrefs

Cf. A002845, A003018, A003019, A145545, A145547, A145548, A145549, A145550, A000081.