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A322880 Number of set partitions of [n] such that the maximal absolute difference between the least elements of consecutive blocks equals seven. 2
0, 1, 67, 1059, 11373, 106256, 940608, 8193031, 71568443, 633413486, 5710573774, 52579554510, 494986212033, 4766754646529, 46966622143740, 473477764449909, 4883216510830794, 51513192445470426, 555667122424414886, 6127026713823497897, 69034256792655555566 (list; graph; refs; listen; history; text; internal format)
OFFSET

7,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 7..580

Wikipedia, Partition of a set

FORMULA

a(n) = A287257(n) - A287256(n).

MAPLE

b:= proc(n, k, m, l) option remember; `if`(n<1, 1,

     `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))

    end:

A:= (n, k)-> b(n-1, min(k, n-1), 1, n):

a:= n-> (k-> A(n, k)-A(n, k-1))(7):

seq(a(n), n=7..30);

CROSSREFS

Column k=7 of A287215.

Cf. A287256, A287257.

Sequence in context: A254640 A093267 A032651 * A157665 A231193 A078850

Adjacent sequences:  A322877 A322878 A322879 * A322881 A322882 A322883

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Dec 29 2018

STATUS

approved

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Last modified July 5 06:34 EDT 2020. Contains 335459 sequences. (Running on oeis4.)