OFFSET
0,5
COMMENTS
T(n, k) = number of integer strings s(0)..s(n) such that s(0) = 0, s(n) = n - 2k, where, for u = 1..n, s(i) is odd if i is odd and |s(i)-s(i-1)| <=1.
LINKS
EXAMPLE
Rows n=0 through n=7:
1
1 ... 1
1 ... 2 ... 1
1 ... 4 ... 4 ... 1
1 ... 5 ... 8 ... 5 ... 1
1 ... 7 ... 17 .. 17 .. 7 ... 1
1 ... 8 ... 24 .. 34 .. 24 .. 8 ... 1
1 ... 10 .. 39 .. 75 .. 75 .. 39 .. 10 ... 1
MAPLE
A026386 := proc(n, k)
option remember;
if k=0 or k = n then
1;
elif k <0 or k > n then
0 ;
elif type(n, 'even') then
procname(n-1, k-1)+procname(n-1, k) ;
else
procname(n-1, k-1)+procname(n-1, k)+procname(n-2, k-1) ;
end if;
end proc: # R. J. Mathar, Feb 10 2015
MATHEMATICA
CROSSREFS
KEYWORD
AUTHOR
EXTENSIONS
Updated by Clark Kimberling, Aug 28 2014
Offset corrected by R. J. Mathar, Feb 10 2015
STATUS
approved