A332947 Number of entries in the seventh blocks of all set partitions of [n] when blocks are ordered by increasing lengths.

1, 57, 1045, 16126, 207131, 2351933, 24592218, 244969609, 2361155669, 22194089013, 205472269667, 1894376413748, 17523281149447, 163348288354057, 1541060427442896, 14781379209476531, 144692817107094283, 1449416720608086968, 14882752251954912426

Offset

7,2

Links

Alois P. Heinz, Table of n, a(n) for n = 7..576

Wikipedia, Partition of a set

Maple

b:= proc(n, i, t) option remember; `if`(n=0, [1, 0], `if`(i>n, 0,
      add((p-> p+`if`(t>0 and t-j<1, [0, p[1]*i], 0))(b(n-i*j, i+1,
      max(0, t-j))/j!*combinat[multinomial](n, i$j, n-i*j)), j=0..n/i)))
    end:
a:= n-> b(n, 1, 7)[2]:
seq(a(n), n=7..25);

Crossrefs

Column k=7 of A319298.

Sequence in context: A008390 A231311 A008922 * A116181 A336734 A333109

Adjacent sequences: A332944 A332945 A332946 * A332948 A332949 A332950

Keyword

nonn

Author

Alois P. Heinz, Mar 03 2020

Status

approved