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A112850
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Number of graph endomorphisms of undirected cycles of even length: |End(C_2n)|.
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2
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2, 32, 132, 576, 2540, 11112, 48076, 205952, 875196, 3695160, 15519548, 64899792, 270415652, 1123264856, 4653525660, 19234572544, 79342611548, 326704870872, 1343120024476, 5513861152880, 22606830726564, 92580354403768, 378737813469692, 1547884976788896, 6320530321887700, 25787763713301512
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OFFSET
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1,1
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REFERENCES
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M. A. Michels, About The Structure of Graph Endomorphisms, Diploma thesis, University of Oldenburg, Germany, 2005
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LINKS
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FORMULA
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|End(C_2n)| = 2n*(2 + binomial(2n-1, n-1) + binomial(2n-1, n)) for n > 1.
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MATHEMATICA
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Join[{2}, Table[2 n (2 + Binomial[2 n - 1, n - 1] + Binomial[2 n - 1, n]), {n, 2, 25}]] (* Vincenzo Librandi, Nov 21 2018 *)
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PROG
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(Magma) [2] cat [2*n*(2 + Binomial(2*n-1, n-1) + Binomial(2*n-1, n)): n in [2..30]]; // Vincenzo Librandi, Nov 21 2018
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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Martin Alexander Michels (martinmichels(AT)t-online.de), Sep 24 2005
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EXTENSIONS
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Corrected first term from 4 to 2 and added "n > 1" in the formula, which is not correct when n=1. - James D. Mitchell (jdm3(AT)st-and.ac.uk), Sep 21 2010
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STATUS
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approved
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