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A320763
Number of ordered set partitions of [n] where the maximal block size equals seven.
2
1, 16, 288, 5280, 101640, 2068704, 44595408, 1017804216, 24559319070, 625388375040, 16772475939648, 472802783660064, 13981054231585584, 432866241024085440, 14006847775868101440, 472893544571144089536, 16631451859811919417144, 608402197372214335559040
OFFSET
7,2
LINKS
FORMULA
E.g.f.: 1/(1-Sum_{i=1..7} x^i/i!) - 1/(1-Sum_{i=1..6} x^i/i!).
a(n) = A276927(n) - A276926(n).
MAPLE
b:= proc(n, k) option remember; `if`(n=0, 1, add(
b(n-i, k)*binomial(n, i), i=1..min(n, k)))
end:
a:= n-> (k-> b(n, k) -b(n, k-1))(7):
seq(a(n), n=7..25);
CROSSREFS
Column k=7 of A276922.
Sequence in context: A218517 A230347 A182608 * A225194 A027776 A140770
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 20 2018
STATUS
approved