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Search: id:A120997
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| A120997 |
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Denominators of partial sums of Catalan numbers scaled by powers of 1/9. |
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+0
2
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| 1, 9, 81, 729, 6561, 19683, 177147, 1594323, 43046721, 387420489, 3486784401, 31381059609, 282429536481, 2541865828329, 2541865828329, 22876792454961, 205891132094649, 5559060566555523, 50031545098999707
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Numerators are given under A120996.
See A120996 for details and a W. Lang link found there for the definition of four p-families of such scaled Catalan sums.
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FORMULA
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a(n)=denominator(r(n)) with r(n) := rI(p=1,n) = sum(C(k)/L(2)^(2*k),k=0..n), with Lucas L(2)=3, and C(k):=A000108(k) (Catalan).
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CROSSREFS
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Sequence in context: A073531 A125910 A125947 this_sequence A125630 A100062 A001019
Adjacent sequences: A120994 A120995 A120996 this_sequence A120998 A120999 A121000
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KEYWORD
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nonn,frac,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Aug 16 2006
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