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Search: id:A079750
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| A079750 |
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Operation count to create all permutations of n distinct elements using the "streamlined" version of Algorithm L (lexicographic permutation generation) from Knuth's The Art of Computer Programming, Vol. 4, chapter 7.2.1.2. Sequence gives number of comparisons required to find j in step L2.2'. |
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+0
11
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| 0, 4, 25, 156, 1099, 8800, 79209, 792100, 8713111, 104557344, 1359245485, 19029436804, 285441552075, 4567064833216, 77640102164689, 1397521838964420, 26552914940323999, 531058298806480000, 11152224274936080021
(list; graph; listen)
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OFFSET
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3,2
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COMMENT
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The asymptotic value for large n is 0.21828...*n! See also comment for A079884
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REFERENCES
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See under A079884
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LINKS
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Hugo Pfoertner, FORTRAN program for lexicographic permutation generation.
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FORMULA
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a(3)=0, a(n) = n * a(n-1) + n for n>=4
Sum((n+1)!/j!,j=3..n). - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 20 2006
For n>=3, a(n)=floor((e-5/2)*n!-1/2). - Benoit Cloitre, Aug 03 2007
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MAPLE
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a:=n->sum((n+1)!/j!, j=3..n): seq(a(n), n=2..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 20 2006
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MATHEMATICA
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a[3] = 0; a[n_] := n*a[n - 1] + n; Table[a[n], {n, 3, 21}]
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PROGRAM
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FORTRAN program available at link
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CROSSREFS
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Cf. A079884, A079751, A079752, A079753, A079754, A079755, A079756.
Adjacent sequences: A079747 A079748 A079749 this_sequence A079751 A079752 A079753
Sequence in context: A055846 A091634 A010909 this_sequence A073517 A074422 A128419
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KEYWORD
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easy,nonn
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AUTHOR
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Hugo Pfoertner (hugo(AT)pfoertner.org), Jan 14 2003
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 22 2003
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