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 A213937 #15 Apr 05 2022 21:26:47
%S A213937 1,2,4,11,42,207,1238,8661,69282,623531,6235302,68588313,823059746,
%T A213937 10699776687,149796873606,2246953104077,35951249665218,
%U A213937 611171244308691,11001082397556422,209020565553572001
%N A213937 Row sums a(n) of triangle A213936: number of representative necklaces with n beads (C_N symmetry) corresponding to all color signatures given by the partitions [1^n], [2,1^(n-2)], ..., [n-1,1], [n].
%C A213937 See A213936 and A212359 for more details, references and links.
%F A213937 a(n) = A002627(n-1) + 1, n>=1.
%F A213937 a(n) = Sum_{k=1..n} A213936(n,k), n>=1.
%F A213937 a(n) = 1 + Sum_{k=1..n-1} (n-1)!/k! = 1 + A002627(n-1), n>=1.
%F A213937 a(n) = 1 + Sum_{k=1..n} A248669(n-1,k), n>=1. - _Greg Dresden_, Mar 31 2022
%e A213937 n=4: the representative necklaces (of a color class) correspond to the color signatures c[.] c[.] c[.] c[.], c[.]^2 c[.] c[.], c[.]^3 c[.]^1 and c[.]^4 (the reverse partition order compared to Abramowitz-Stegun without 2^2). The corresponding necklaces are (we use j for color c[j]): cyclic(1234), coming in all-together 6 permutations of the present colors, cyclic(1123) coming in 3 permutions, cyclic(1112) and cyclic(1111), adding up to the 11 = a(4) necklaces. Not all 4 colors are present, except for the first signature (partition).
%Y A213937 Cf. A002627, A231936, A248669.
%K A213937 nonn,easy
%O A213937 1,2
%A A213937 _Wolfdieter Lang_, Jul 10 2012