OFFSET
0,9
FORMULA
G.f. for column k: x^k/p(k) where p(0)=1, p(1)=1-x, p(n)=(1-x)p(n-1)-(x^2)p(n-2).
EXAMPLE
Rows from n=0: {1}; {0,1}; {0,1,1}; {0,1,2,1}; {0,1,4,3,1}; ...
[1,1,1,2],[1,1,2,2],[1,2,1,2],[1,2,2,2] are the T(4,2)=4 sequences.
PROG
(PARI) T(n, k)=local(p0, p1, p2); if(k<0 || k>n, 0, p1=1; for(i=1, k, p2=(1-x)*p1-x^2*p0; p0=p1; p1=p2); polcoeff(x^k/p1+x*O(x^n), n))
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Michael Somos, Oct 01 2003
STATUS
approved