A037289 - OEIS

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A037289

Number of commutative rings with n elements.

1, 2, 2, 9, 2, 4, 2, 34, 9, 4, 2, 18, 2, 4, 4, 162, 2, 18, 2, 18, 4, 4, 2, 68, 9, 4, 36, 18, 2, 8, 2 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`This sequence may be multiplicative. - Mitch Harris, Apr 19 2005`
	LINKS	`C. Noebauer, Home page` `C. Noebauer, The Numbers of Small Rings` `C. Noebauer, Thesis on the enumeration of near-rings`
	CROSSREFS	`Cf. A027623, A037291.` `Sequence in context: A199058 A082838 A074961 * A037290 A155936 A167594` `Adjacent sequences: A037286 A037287 A037288 * A037290 A037291 A037292`
	KEYWORD	`nonn,nice,hard`
	AUTHOR	`Christian G. Bower (bowerc(AT)usa.net), Jun 15 1998.`
	EXTENSIONS	`a(16) from Christof Noebauer (christof.noebauer(AT)algebra.uni-linz.ac.at), Sep 29, 2000, who reports that the sequence continues a(32) = ? (> 876), a(33) = 4, 4, 4, 81, 2, 4, 4, 68, 2, 8, 2, 18, 18, 4, 2, 324, 9, 18, 4, 18, 2, 72, 4, 68, 4, 4, 2, 36, 2, 4, 18 = a(63), a(64) = ? (> 12696)`

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Last modified February 16 06:08 EST 2012. Contains 205860 sequences.