OFFSET
0,5
COMMENTS
T(n,k) is the number of multisets of exactly k binary words with a total of n letters and each word beginning with 1. T(4,2) = 7: {1,100}, {1,101}, {1,110}, {1,111}, {10,10}, {10,11}, {11,11}. - Alois P. Heinz, Sep 18 2017
LINKS
FORMULA
G.f.: 1 / Product_{j>=1} (1-y*x^j)^(2^(j-1)). - Alois P. Heinz, Sep 18 2017
EXAMPLE
The triangle starts:
1;
0 1;
0 2 1;
0 4 2 1;
0 8 7 2 1;
0 16 16 7 2 1;
0 32 42 20 7 2 1;
0 64 96 54 20 7 2 1;
0 128 228 140 59 20 7 2 1;
0 256 512 360 156 59 20 7 2 1;
0 512 1160 888 422 162 59 20 7 2 1;
0 1024 2560 2168 1088 442 162 59 20 7 2 1;
(...)
MAPLE
b:= proc(n, i, p) option remember; `if`(p>n, 0, `if`(n=0, 1,
`if`(min(i, p)<1, 0, add(binomial(2^(i-1)+j-1, j)*
b(n-i*j, i-1, p-j), j=0..min(n/i, p)))))
end:
T:= (n, k)-> b(n$2, k):
seq(seq(T(n, k), k=0..n), n=0..14); # Alois P. Heinz, Sep 12 2017
MATHEMATICA
b[n_, i_, p_] := b[n, i, p] = If[p > n, 0, If[n == 0, 1, If[Min[i, p] < 1, 0, Sum[Binomial[2^(i - 1) + j - 1, j] b[n - i j, i - 1, p - j], {j, 0, Min[n/i, p]}]]]];
T[n_, k_] := b[n, n, k];
Table[Table[T[n, k], {k, 0, n}], {n, 0, 14}] // Flatten (* Jean-François Alcover, Dec 07 2019, after Alois P. Heinz *)
CROSSREFS
The reverse of the n-th row converges to A034899.
KEYWORD
nonn,tabl
AUTHOR
M. F. Hasler, Jul 24 2017
STATUS
approved