login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A026763 a(n) = T(2n-1,n-2), T given by A026758. 10
1, 7, 38, 190, 918, 4365, 20594, 96804, 454362, 2132121, 10010203, 47042042, 221337726, 1042837195, 4920447410, 23250646651, 110029743083, 521462857972, 2474929099976, 11762845907633, 55982738983975, 266789302547057 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,2
LINKS
MAPLE
T:= proc(n, k) option remember;
if n<0 then 0;
elif k=0 or k = n then 1;
elif type(n, 'odd') and k <= (n-1)/2 then
procname(n-1, k-1)+procname(n-2, k-1)+procname(n-1, k) ;
else
procname(n-1, k-1)+procname(n-1, k) ;
end if ;
end proc;
seq(T(2*n-1, n-2), n=2..30); # G. C. Greubel, Oct 31 2019
MATHEMATICA
T[n_, k_]:= T[n, k]= If[n<0, 0, If[k==0 || k==n, 1, If[OddQ[n] && k<=(n - 1)/2, T[n-1, k-1] + T[n-2, k-1] + T[n-1, k], T[n-1, k-1] + T[n-1, k] ]]]; Table[T[2n-1, n-2], {n, 2, 30}] (* G. C. Greubel, Oct 31 2019 *)
PROG
(Sage)
@CachedFunction
def T(n, k):
if (n<0): return 0
elif (k==0 or k==n): return 1
elif (mod(n, 2)==1 and k<=(n-1)/2): return T(n-1, k-1) + T(n-2, k-1) + T(n-1, k)
else: return T(n-1, k-1) + T(n-1, k)
[T(2*n-1, n-2) for n in (2..30)] # G. C. Greubel, Oct 31 2019
CROSSREFS
Sequence in context: A291822 A099453 A292535 * A217340 A037696 A026895
KEYWORD
nonn
AUTHOR
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 25 12:23 EDT 2024. Contains 373701 sequences. (Running on oeis4.)