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A145547
Number of distinct values taken by 7^7^...^7 (with n 7's and parentheses inserted in all possible ways).
15
1, 1, 2, 4, 9, 20, 48, 115, 286, 719, 1841, 4762, 12470, 32918, 87628, 234795, 633000, 1715435, 4671098, 12772707, 35059815, 96567161, 266818396, 739344427
OFFSET
1,3
KEYWORD
more,nonn
AUTHOR
Jon E. Schoenfield, Oct 13 2008
STATUS
approved