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A209412 Number of nonisomorphic semigroups of order 2^n. 0
1, 5, 188, 3684030417 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

This is to A000679 as semigroups are to groups.

LINKS

Table of n, a(n) for n=0..3.

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 * A138733 A222363 A316330

Adjacent sequences:  A209409 A209410 A209411 * A209413 A209414 A209415

KEYWORD

nonn,hard

AUTHOR

Jonathan Vos Post, Mar 08 2012

STATUS

approved

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Last modified August 12 17:17 EDT 2020. Contains 336439 sequences. (Running on oeis4.)