A327847 Number of colored compositions of n using all colors of a 2-set such that all parts have different color patterns and the patterns for parts i have i colors in (weakly) increasing order.
0, 0, 3, 10, 39, 100, 303, 782, 2009, 5388, 12839, 32658, 79673, 191500, 459745, 1090622, 2569597, 5932304, 13906405, 31740090, 72160311, 164296384, 369673125, 827781598, 1834885695, 4076433368, 8966677703, 19639987986, 42751905899, 92703023676, 200647122467
Offset: 0
Keywords
Examples
a(3) = 10: 3aab, 3abb, 2aa1b, 2ab1a, 2ab1b, 2bb1a, 1a2ab, 1a2bb, 1b2aa, 1b2ab.
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..800
Crossrefs
Column k=2 of A327245.
Programs
-
Maple
b:= proc(n, i, k, p) option remember; `if`(n=0, p!, `if`(i<1, 0, add(b(n-i*j, min(n-i*j, i-1), k, p+j)* binomial(binomial(k+i-1, i), j), j=0..n/i))) end: a:= n-> (k-> add(b(n$2, i, 0)*(-1)^(k-i)*binomial(k, i), i=0..k))(2): seq(a(n), n=0..37);