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Search: id:A002489
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| A002489 |
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n^(n^2) (or (n^n)^n).
(Formerly M5030 N2170)
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+0
42
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| 1, 1, 16, 19683, 4294967296, 298023223876953125, 10314424798490535546171949056, 256923577521058878088611477224235621321607, 6277101735386680763835789423207666416102355444464034512896, 196627050475552913618075908526912116283103450944214766927315415537966391196809
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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The number of closed binary operations on a set of order n. Labeled groupoids.
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REFERENCES
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J. S. Rose, A Course on Group Theory, Camb. Univ. Press, 1978, see p. 6.
P. Rossier, Grands nombres, Elemente der Mathematik, 3 (1948), 20.
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LINKS
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Eric Postpischil Posting to sci.math newsgroup, May 21 1990
Index entries for sequences related to groupoids
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EXAMPLE
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a(3) = 19683 because (3^3)^3 = 3^(3^2) = 19683.
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MAPLE
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seq(mul(mul(j*n/k, j=1..n), k=1..n), n=0..9); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 02 2007
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CROSSREFS
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a(n)=A079172(n)+A023814(n)=A079176(n)+A079179(n)
a(n)=A079182(n)+A023813(n)=A079186(n)+A079189(n)
a(n)=A079192(n)+A079195(n)+A079198(n)+A023185(n)
Cf. A002488.
Cf. A001329, A002488, A023813, A076113, A090588
Sequence in context: A013831 A098175 A089232 this_sequence A060205 A140597 A017296
Adjacent sequences: A002486 A002487 A002488 this_sequence A002490 A002491 A002492
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KEYWORD
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nonn,easy,nice
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AUTHOR
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njas
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