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%I #5 Mar 27 2016 14:26:37
%S 1,21,197,1421,9573,64724,449567,3230230,24053169,185658621,
%T 1484943532,12299106220,105400873263,933717036862,8541991253431,
%U 80620086997245,784225175253212,7854824886117957,80933906884404094,857116366195307414,9321782438290435408
%N Number of set partitions of [n] having exactly three pairs (m,m+1) such that m+1 is in some block b and m is in block b+1.
%H Alois P. Heinz, <a href="/A270957/b270957.txt">Table of n, a(n) for n = 6..220</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Partition_of_a_set">Partition of a set</a>
%e a(6) = 1: 136|25|4.
%e a(7) = 21: 1247|36|5, 1347|26|5, 1357|246, 135|247|6, 137|246|5, 1367|25|4, 136|257|4, 136|25|47, 136|25|4|7, 137|256|4, 13|257|46, 13|25|47|6, 137|26|45, 13|27|46|5, 147|236|5, 157|246|3, 15|247|36, 15|24|37|6, 17|246|35, 1|247|36|5, 17|26|35|4.
%Y Column k=3 of A270953.
%K nonn
%O 6,2
%A _Alois P. Heinz_, Mar 26 2016
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