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A137697 a(n) = x(n) * 2^((n mod 2 - 1)/2), with x(n)=Sum(x(k)*x(n-k-1):0<=k<n), x(0)=SQRT(2). 1
1, 2, 4, 20, 56, 336, 1056, 6864, 22880, 155584, 537472, 3762304, 13312768, 95091200, 342328320, 2481880320, 9051563520, 66378132480 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..17.

EXAMPLE

x(1) = 2;

x(2) = 5.6568... = a(2)*SQRT(2);

x(3) = 20;

x(4) = 79.1959... = a(4)*SQRT(2);

x(5) = 336;

x(6) = 1493.4095... = a(6)*SQRT(2).

CROSSREFS

Cf. A000108.

Sequence in context: A294230 A052004 A027741 * A192380 A009336 A274520

Adjacent sequences:  A137694 A137695 A137696 * A137698 A137699 A137700

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Feb 06 2008

STATUS

approved

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Last modified January 17 18:28 EST 2018. Contains 297829 sequences.