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A072827
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Number of permutations satisfying i-2<=p(i)<=i+3, i=1..n.
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67
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1, 2, 6, 18, 46, 115, 301, 792, 2068, 5380, 14020, 36581, 95413, 248786, 648714, 1691686, 4411530, 11503991, 29998953, 78228640, 203998184, 531969064, 1387222648, 3617479225, 9433351129, 24599481138, 64148406350, 167280683834
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| R. H. Hardin, Table of n, a(n) for n=1..400, Jul 11 2010
Index entries for sequences related to linear recurrences with constant coefficients, signature (1,2,3,5,6,-1,-1,0,-1,-1).
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FORMULA
| Recurrence: a(n) = a(n-1)+2*a(n-2)+3*a(n-3)+5*a(n-4)+6*a(n-5)-a(n-6)-a(n-7)-a(n-9)-a(n-10). G.f.: (x^5+x^3+x^2-1)/(x^10+x^9+x^7+x^6-6*x^5-5*x^4-3*x^3-2*x^2-x+1).
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CROSSREFS
| Cf. A000045, A000073, A002524, A002526.
Sequence in context: A120414 A054136 A140960 * A002529 A018027 A059413
Adjacent sequences: A072824 A072825 A072826 * A072828 A072829 A072830
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KEYWORD
| nonn,easy
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AUTHOR
| Vladimir Baltic (baltic(AT)matf.bg.ac.yu), Jul 21 2002
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