This site is supported by donations to The OEIS Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A166232 a(n) = A166231(n)/4^n. 5
 1, 1, 3, 20, 272, 7424, 405504, 44302336, 9680453632, 4230542786560, 3697657604210688, 6463791365183504384, 22598414411798807576576, 158015104883301198495481856, 2209780998563745292895322636288 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(n+1) is the Hankel transform of A068764. LINKS G. C. Greubel, Table of n, a(n) for n = 0..70 FORMULA a(n) = 2^C(n,2)*Sum_{k=0..floor(n/2)} C(n,2k)*2^(-k). a(n) = A166231(n)/4^n. MATHEMATICA Table[2^(Binomial[n, 2])*Sum[Binomial[n, 2 k]*2^(-k), {k, 0, Floor[n/2]}], {n, 0, 25}] (* G. C. Greubel, May 07 2016 *) CROSSREFS Cf. A068764, A166231. Sequence in context: A210906 A193194 A320945 * A136551 A266812 A086229 Adjacent sequences:  A166229 A166230 A166231 * A166233 A166234 A166235 KEYWORD easy,nonn AUTHOR Paul Barry, Oct 09 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 19 17:45 EST 2019. Contains 319309 sequences. (Running on oeis4.)