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Search: id:A135594
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| A135594 |
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a(n) = (1/2^n) * sum_{i=0..n}(-1)^(n-i)* binomial(n, i) * A000364(i). |
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+0
1
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| 1, 0, 1, 6, 73, 1380, 37801, 1417626, 69802993, 4369750440, 339034806001, 31935510092046, 3590398569115513, 474937566660074700, 73024143791301120601, 12914495107705743175266, 2603190607000627341985633
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983, Exercise 4.2.2.(b).
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MAPLE
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A000364 := proc(n) option remember ; (2*n)!*coeftayl(sec(x), x=0, 2*n) ; end: A135594 := proc(n) add((-1)^(n-i)*binomial(n, i)*A000364(i), i=0..n)/2^n ; end: seq(A135594(n), n=0..20) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 14 2008
f:=sec(z): fser:=series(f, z=0, 63): for n from 0 to 60 do b[n]:=factorial(n)*coeff(fser, z, n) end do: a:= proc(n) options operator, arrow: add((-1)^(n-k)*binomial(n, k)*b[2*k], k=0..n)/2^n end proc: seq(a(n), n=0..16); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 17 2008
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CROSSREFS
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Cf. A005799.
Sequence in context: A105324 A041060 A089926 this_sequence A058793 A066171 A057783
Adjacent sequences: A135591 A135592 A135593 this_sequence A135595 A135596 A135597
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)Eunet.yu), Feb 25 2008
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl) and Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 03 2008
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