A145545 Number of distinct values taken by 5^5^...^5 (with n 5's and parentheses inserted in all possible ways).

1, 1, 2, 4, 9, 20, 48, 115, 285, 715, 1826, 4711, 12303, 32387, 85964, 229662, 617300, 1667787, 4527290, 12340688, 33766612, 92707834, 255329106

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.
• MathOverflow, MathOverflow discussion of related questions
• Index entries for sequences related to parenthesizing

Crossrefs

Cf. A002845, A003018, A003019, A145546, A145547, A145548, A145549, A145550, A000081.