# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a271791 Showing 1-1 of 1 %I A271791 #5 Apr 14 2016 12:59:15 %S A271791 0,1,15,129,891,5611,34213,208230,1285094,8108722,52540098,350375379, %T A271791 2407395908,17048774736,124435165429,935736058614,7246161094614, %U A271791 57749473020305,473358586652328,3987856784525223,34506189729577186,306454001139880689,2791593349164080381 %N A271791 Number of set partitions of [n] having exactly four pairs (m,m+1) such that m is in some block b and m+1 is in block b+1. %H A271791 Alois P. Heinz, Table of n, a(n) for n = 4..300 %e A271791 a(5) = 1: 1|2|3|4|5. %e A271791 a(6) = 15: 12|3|4|5|6, 13|24|5|6, 1|23|4|5|6, 14|25|36, 1|24|35|6, 1|2|34|5|6, 15|26|3|4, 1|25|36|4, 1|2|35|46, 1|2|3|45|6, 16|2|3|4|5, 1|26|3|4|5, 1|2|36|4|5, 1|2|3|46|5, 1|2|3|4|56. %Y A271791 Column k=4 of A185982. %K A271791 nonn %O A271791 4,3 %A A271791 _Alois P. Heinz_, Apr 14 2016 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE