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Search: id:A059371
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| A059371 |
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a(n) = (n-1)!+((n+1)/2)*a(n-1), a(1)=0. |
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+0
6
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| 1, 4, 16, 72, 372, 2208, 14976, 115200, 996480, 9607680, 102366720, 1195568640, 15193785600, 208728576000, 3081867264000, 48659595264000, 817953583104000, 14581909536768000, 274755150544896000, 5455208664170496000, 113825841809670144000
(list; graph; listen)
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OFFSET
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2,2
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REFERENCES
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L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 171, #34.
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LINKS
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Harry J. Smith, Table of n, a(n) for n=2,...,200
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FORMULA
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E.g.f.: (x^2-2*x-2*ln(1-x))/(x-2)^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), May 04 2003
Sum of i!*(n-i+1)!. E.g. a(5) = 1!*5!+2!4!+3!3!+4!2!+5!1! = 120+48+36+48+120 = 372 - Jon Perry (perry(AT)globalnet.co.uk), May 06 2006
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PROGRAM
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(PARI) a(n)=sum(i=1, n, i!*(n-i+1)!) - Jon Perry (perry(AT)globalnet.co.uk), May 06 2006
(PARI) { a=0; for (n = 2, 200, write("b059371.txt", n, " ", a = (n - 1)! + a*(n + 1)/2); ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jun 26 2009]
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CROSSREFS
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Second diagonal of triangle in A059369.
Sequence in context: A151246 A152807 A129872 this_sequence A007234 A096244 A030131
Adjacent sequences: A059368 A059369 A059370 this_sequence A059372 A059373 A059374
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Jan 28 2001
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EXTENSIONS
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Better description from Vladeta Jovovic (vladeta(AT)eunet.rs), May 04 2003
More terms from Larry Reeves (larryr(AT)acm.org), Jan 31 2001
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