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Search: id:A049027
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| A049027 |
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G.f.: (1-2*x*C)/(1-3*x*C) where C = (1/2-1/2*(1-4*x)^(1/2))/x = g.f. for Catalan numbers A000108. |
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+0
17
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| 1, 1, 4, 17, 74, 326, 1446, 6441, 28770, 128750, 576944, 2587850, 11615932, 52167688, 234383146, 1053386937, 4735393794, 21291593238, 95747347176, 430624242942, 1936925461644, 8712882517188, 39195738193836, 176335080590442
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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W. Lang, On generalizations of Stirling number triangles, J. Integer Seqs., Vol. 3 (2000), #00.2.4.
J. W. Layman, The Hankel Transform and Some of its Properties, J. Integer Sequences, 4 (2001), #01.1.5.
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FORMULA
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G.f.: x*c(x)/(1-3*x*c(x)), c(x)= g.f. of Catalan numbers A000108.
a(n+1)=sum{k=0..n, 2^k*comb(2n+1, n-k)2(k+1)/(n+k+2)} - Paul Barry (pbarry(AT)wit.ie), Jun 22 2004
a(n) = (9*a(n-1)-Catalan(n-1))/2, n>1. - Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 08 2004
a(n+1)=Sum_{k, 0<=k<=n}A039598(n,k)*2^k . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Mar 21 2007
G.f.: 2/ (3 -1/sqrt(1 -4*x)) . - Michael Somos Apr 08 2007
a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*A001045(k), for n>=1 . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jun 10 2007
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PROGRAM
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(PARI) {a(n)= if(n<1, n==0, polcoeff( serreverse( x*(1 +2*x)/ (1 +3*x)^2 +x*O(x^n) ), n))} /* Michael Somos Apr 08 2007 */
(PARI) {a(n)= if(n<0, 0, polcoeff( 2/ (3 -1/sqrt(1 -4*x +x*O(x^n))), n))} /* Michael Somos Apr 08 2007 */
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CROSSREFS
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Row sums of triangle A035324. Cf. A000108, A001700.
Sequence in context: A095940 A125586 A086351 this_sequence A026751 A081568 A026378
Adjacent sequences: A049024 A049025 A049026 this_sequence A049028 A049029 A049030
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KEYWORD
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easy,nonn
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)
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