login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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; internal format)
OFFSET

0,2

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: A059206 A052004 A027741 * A192380 A009336 A192377

Adjacent sequences:  A137694 A137695 A137696 * A137698 A137699 A137700

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 06 2008

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 16 19:48 EST 2012. Contains 205955 sequences.