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A076025 G.f.: (1-3*x*C)/(1-4*x*C) where C = (1/2-1/2*(1-4*x)^(1/2))/x = g.f. for Catalan numbers A000108. +0
13
1, 1, 5, 26, 137, 726, 3858, 20532, 109361, 582782, 3106550, 16562668, 88314634, 470942044, 2511443268, 13393472616, 71428622337, 380940866574, 2031641406798, 10835261623356, 57787472903502, 308197667445204, 1643712737618748, 8766437439778776, 46754218658948922 (list; graph; listen)
OFFSET

0,3

COMMENT

Contribution from Paul Barry (pbarry(AT)wit.ie), Sep 23 2009: (Start)

The Hankel transform of this sequence is 3n+1 or 1,4,7,10,... (A016777).

The Hankel transform of the aeration of this sequence is A016777 doubled, that is, 1,1,4,4,7,7,...

In general, the Hankel transform of [x^n](1-r*xc(x))/(1-(r+1)*xc(x)) is rn+1, and that of the

corresponding aerated sequence is the doubled sequence of rn+1. (End)

FORMULA

a(n+1)=sum{k=0..n, 3^k*comb(2n+1, n-k)2(k+1)/(n+k+2)} - Paul Barry (pbarry(AT)wit.ie), Jun 22 2004

a(n+1)=Sum_{k, 0<=k<=n}A039598(n,k)*3^k . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Mar 21 2007

a(n) = Sum_{k, 0<=k<=n}A039599(n,k)*A015518(k), for n>=1 . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 22 2007

CROSSREFS

Cf. A000108, A001700, A049027, A076026.

Sequence in context: A052918 A018903 A083331 this_sequence A161731 A049607 A035029

Adjacent sequences: A076022 A076023 A076024 this_sequence A076026 A076027 A076028

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Oct 29 2002

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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