OFFSET
0,8
LINKS
Alois P. Heinz, Antidiagonals n = 0..20, flattened
EXAMPLE
Square array A(n,k) begins:
1, 1, 1, 1, 1, 1, ...
1, 1, 3, 7, 15, 31, ...
1, 1, 13, 157, 2101, 32461, ...
1, 1, 63, 5419, 717795, 142090291, ...
1, 1, 321, 220561, 328504401, 944362553521, ...
1, 1, 1683, 9763807, 172924236255, 7622403922836151, ...
MAPLE
s:= proc(n) option remember; `if`(n=0, {[]},
map(x-> [[x[], 0], [x[], 1]][], s(n-1)))
end:
b:= proc(l) option remember; `if`(l=[] or l[1]=0, 1,
add((p-> `if`(p[1]<0, 0, `if`(p[1]=0, 1, b(p)))
)(sort(l-x)), x=s(nops(l)) minus {[0$nops(l)]}))
end:
A:= (n, k)-> b([n$k]):
seq(seq(A(n, d-n), n=0..d), d=0..10);
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Alois P. Heinz, Oct 11 2015
STATUS
approved