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A007121
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E.g.f. ( (1+x)^x )^x.
(Formerly M4099)
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1
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1, 0, 0, 6, -12, 40, 180, -1512, 11760, -38880, 20160, 2106720, -22381920, 173197440, -703999296, -1737489600, 86030380800, -1149696737280, 11455162974720, -89560399541760, 636617260339200, -6318191386644480, 139398889956480000, -3797936822885990400
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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REFERENCES
| N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| a(n)= n!*sum{k=0..n/2} stirling1(n-2*k,k)/(n-2*k)! . - Vladimir Kruchinin, Dec 13 2011
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MAPLE
| A007121 := proc(n)
n!*coeftayl( (1+x)^(x^2), x=0, n) ;
end proc:
seq(A007121(n), n=0..40) ; # R. J. Mathar, Dec 15 2011
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PROG
| (Maxima)
a(n):=sum(stirling1(n-2*k, k)/(n-2*k)!, k, 0, n/2); /* Vladimir Kruchinin, Dec 13 2011 */
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CROSSREFS
| Sequence in context: A128453 A185616 A052747 * A152786 A206039 A048069
Adjacent sequences: A007118 A007119 A007120 * A007122 A007123 A007124
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KEYWORD
| sign
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AUTHOR
| Simon Plouffe (simon.plouffe(AT)gmail.com)
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EXTENSIONS
| Signs added by R. J. Mathar, V. Kruchinin, Dec 15 2011
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