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 A303588 #7 Feb 07 2025 12:01:41 %S A303588 1,0,2,2,7,12,32,67,169,390,985,2412,6209,15871,41867,110797,299836, %T A303588 817612,2268640,6354409,18058764,51838340,150704087,442550971, %U A303588 1314527780,3943140077,11953192954,36580095663,113048257691,352564213025,1109727658303 %N A303588 Number of partitions of n that contain exactly two isolated singletons. %H A303588 A. O. Munagi, <a href="https://doi.org/10.1080/00029890.2018.1430960">Set partitions with isolated singletons</a>, Am. Math. Monthly 125 (2018), 447-452. %p A303588 f:=proc(n,r) local j; %p A303588 add(combinat:-bell(j-1)*binomial(n-j-1,j-r-1),j=1..floor((n+r)/2)); %p A303588 end; %p A303588 [seq(f(n,2),n=2..40)]; %Y A303588 Cf. A211694, A303587. %K A303588 nonn %O A303588 2,3 %A A303588 _N. J. A. Sloane_, May 19 2018