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A209412
Number of nonisomorphic semigroups of order 2^n.
0
1, 5, 188, 3684030417
OFFSET
0,2
COMMENTS
This is to A000679 as semigroups are to groups.
FORMULA
a(n) = A027851(A000079(n)).
EXAMPLE
a(3) = 3684030417 because there are 3684030417 nonisomorphic semigroups of order 2^3 = 8.
CROSSREFS
Cf. A000079, A000679 Number of groups of order 2^n, A027851 Number of nonisomorphic semigroups of order n.
Sequence in context: A208410 A268001 A096543 * A353879 A138733 A222363
KEYWORD
nonn,hard
AUTHOR
Jonathan Vos Post, Mar 08 2012
STATUS
approved