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Search: id:A093986
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| A093986 |
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a(1) = 1, a(2) = 1, a(n+1) = 2n*a(n) - a(n-1). Symmetrically a(n) = {a(n-1)+a(n+1)}/{(n-1) +(n+1)}. |
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3
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| 1, 1, 3, 17, 133, 1313, 15623, 217409, 3462921, 62115169, 1238840459, 27192374929, 651378157837, 16908639728833, 472790534249487, 14166807387755777, 452865045873935377, 15383244752326047041, 553343946037863758099
(list; graph; listen)
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OFFSET
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1,3
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MAPLE
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a[1]:=1:a[2]:=1:for n from 3 to 21 do a[n]:=2*(n-1)*a[n-1]-a[n-2] od: seq(a[n], n=1..21); (Deutsch)
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CROSSREFS
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Cf. A093985.
Sequence in context: A073513 A074524 A163684 this_sequence A055214 A105630 A006290
Adjacent sequences: A093983 A093984 A093985 this_sequence A093987 A093988 A093989
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 22 2004
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Apr 17 2005
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