The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A180966 Hankel transform of A123164. 1
 1, 4, 28, 384, 10496, 573440, 62652416, 13690208256, 5982889443328, 5229277301702656, 9141181343655264256, 31958984107701798174720, 223467104335874481157308416, 3125102257923487167715657908224 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA a(n) = 2^C(n,2)*sum{k=0..floor(n/2), C(n-k,k)*(-2)^k*4^(n-2k)}; a(n) = 2^C(n,2)*[x^n](1/(1-4x+2x^2)). a(n) = 2^(2*n+((n-1)*n)/2)*Hyper2F1([1/2-n/2, -n/2], [-n], 1/2) for n>0. - Peter Luschny, Aug 02 2014 MATHEMATICA a[n_] := 2^Binomial[n, 2] Sum[Binomial[n-k, k] (-2)^k 4^(n-2k), {k, 0, n/2} ]; Table[a[n], {n, 0, 13}] (* Jean-François Alcover, Jun 17 2019 *) CROSSREFS Sequence in context: A095288 A155105 A132685 * A203032 A086812 A197872 Adjacent sequences:  A180963 A180964 A180965 * A180967 A180968 A180969 KEYWORD easy,nonn AUTHOR Paul Barry, Sep 29 2010 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 February 23 00:28 EST 2020. Contains 332157 sequences. (Running on oeis4.)