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A303588 Number of partitions of n that contain exactly two isolated singletons. 2
1, 0, 2, 2, 7, 12, 32, 67, 169, 390, 985, 2412, 6209, 15871, 41867, 110797, 299836, 817612, 2268640, 6354409, 18058764, 51838340, 150704087, 442550971, 1314527780, 3943140077, 11953192954, 36580095663, 113048257691, 352564213025, 1109727658303 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,3
LINKS
A. O. Munagi, Set partitions with isolated singletons, Am. Math. Monthly 125 (2018), 447-452.
MAPLE
f:=proc(n, r) local j;
add(combinat:-bell(j-1)*binomial(n-j-1, j-r-1), j=1..floor((n+r)/2));
end;
[seq(f(n, 2), n=2..40)];
CROSSREFS
Sequence in context: A024309 A047756 A047767 * A366583 A366584 A019144
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 19 2018
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)