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A112556 Sums of squared terms in rows of triangle A112555. 4
1, 2, 2, 4, 10, 32, 112, 408, 1514, 5680, 21472, 81644, 311896, 1196132, 4602236, 17757184, 68680170, 266200112, 1033703056, 4020716124, 15662273840, 61092127492, 238582873476, 932758045124, 3650336341240, 14298633670932, 56055986383412, 219931273282348, 863504076182884, 3392593262288780, 13337336618626132 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

First differences form A072547 and equals the unsigned central terms of triangle A112555.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

FORMULA

G.f.: ( 2*(1+x)/(1-x) + x/(1-4*x)^(1/2) )/(2+x).

a(n) ~ 2^(2*n) / (9*sqrt(Pi*n)). - Vaclav Kotesovec, Mar 26 2016

MATHEMATICA

CoefficientList[Series[(2(1+x)/(1-x)+x/(1-4x)^(1/2))/(2+x), {x, 0, 30}], x] (* Harvey P. Dale, May 26 2011 *)

PROG

(PARI) {a(n)=local(x=X+X*O(X^n)); polcoeff((2*(1+x)/(1-x)+x/(1-4*x)^(1/2))/(2+x), n, X)}

CROSSREFS

Cf. A112555, A072547.

Sequence in context: A078801 A002420 A284016 * A254400 A054100 A034165

Adjacent sequences:  A112553 A112554 A112555 * A112557 A112558 A112559

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Sep 21 2005

STATUS

approved

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Last modified October 22 06:02 EDT 2018. Contains 316432 sequences. (Running on oeis4.)