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Number of set partitions of [n] having exactly three pairs (m,m+1) such that m is in some block b and m+1 is in block b+1.
2

%I #5 Apr 14 2016 12:21:11

%S 0,1,10,61,313,1520,7373,36627,188396,1007708,5612677,32551400,

%T 196447095,1232448403,8028591686,54240974862,379574487845,

%U 2748022434268,20558256639096,158746877185099,1263892981174760,10364745848886935,87464284123646375,758804198576946316

%N Number of set partitions of [n] having exactly three pairs (m,m+1) such that m is in some block b and m+1 is in block b+1.

%H Alois P. Heinz, <a href="/A271790/b271790.txt">Table of n, a(n) for n = 3..300</a>

%e a(4) = 1: 1|2|3|4.

%e a(5) = 10: 12|3|4|5, 13|24|5, 1|23|4|5, 14|25|3, 1|24|35, 1|2|34|5, 15|2|3|4, 1|25|3|4, 1|2|35|4, 1|2|3|45.

%Y Column k=3 of A185982.

%K nonn

%O 3,3

%A _Alois P. Heinz_, Apr 14 2016