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A289681
Number of closed simply-typed normal forms of size n.
0
1, 2, 6, 23, 108, 618, 4092, 30413, 252590, 2297954, 22640259, 240084189, 2721455329, 32783910297
OFFSET
1,2
CROSSREFS
Sequence in context: A297196 A112501 A093345 * A002136 A328441 A328507
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Aug 04 2017
STATUS
approved