This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A271789 #5 Apr 14 2016 11:50:54 %S A271789 0,1,6,24,86,307,1143,4513,18956,84546,399218,1989792,10439521, %T A271789 57504306,331747730,1999924893,12571830681,82245682149,558951842996, %U A271789 3939679356783,28754596249395,217019729585609,1691485555633721,13598390501982510,112633410446366669 %N A271789 Number of set partitions of [n] having exactly two pairs (m,m+1) such that m is in some block b and m+1 is in block b+1. %H A271789 Alois P. Heinz, <a href="/A271789/b271789.txt">Table of n, a(n) for n = 2..400</a> %e A271789 a(3) = 1: 1|2|3. %e A271789 a(4) = 6: 12|3|4, 13|24, 1|23|4, 14|2|3, 1|24|3, 1|2|34. %e A271789 a(5) = 24: 123|4|5, 124|35, 12|34|5, 125|3|4, 12|35|4, 12|3|45, 134|25, 135|24, 13|245, 13|2|4|5, 14|235, 1|234|5, 15|23|4, 1|235|4, 1|23|45, 145|2|3, 14|2|35, 14|2|3|5, 15|24|3, 1|245|3, 1|24|3|5, 15|2|34, 1|25|34, 1|2|345. %Y A271789 Column k=2 of A185982. %K A271789 nonn %O A271789 2,3 %A A271789 _Alois P. Heinz_, Apr 14 2016