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Search: id:A119913
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| A119913 |
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Number of different simple cycles in the complete graph K_n; that is, the number of subsets of at least 3 elements out of n, ordered up to cyclic permutations. |
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+0
1
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| 0, 0, 2, 14, 74, 394, 2344, 16036, 125628, 1112028, 10976118, 119481218, 1421542550
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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a(n) = Sum_{k=3..n} (n choose k) * (k-1)! ; a(n) = Sum_{i=2..n-1}(Floor(e*i!)) - (n+3)(n-2)/2 ; a(n) = Sum_{k=1..n-1} A038154(k)
a(n) = 2*A002807(n). - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 04 2006
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EXAMPLE
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a(4)=14 because there are 6 4-cycles and 8 3-cycles.
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PROGRAM
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Matlab: function a = an(n) s = 0; for i = 2:n-1 s = s+fix(exp(1)*factorial(i)); end a = s - (n+3)*(n-2)/2;
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CROSSREFS
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Cf. A038154.
Sequence in context: A095933 A043011 A138156 this_sequence A104871 A034573 A133224
Adjacent sequences: A119910 A119911 A119912 this_sequence A119914 A119915 A119916
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KEYWORD
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nonn
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AUTHOR
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Amir M. Ben-Amram (amirben(AT)mta.ac.il), Aug 02 2006
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