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 A005957 M0880 #22 Jul 08 2025 16:39:43
%S A005957 1,1,2,3,8,18,47,123,338,935,2657,7616,22138,64886,191873,571169,
%T A005957 1711189,5153883,15599094,47415931,144692886,443091572,1361233280,
%U A005957 4194107380,12957209782,40128629400,124562327944,387467513732,1207633413980
%N A005957 Number of acyclic ketone and aldehyde stereo-isomers with n carbon atoms.
%C A005957 It seems that, starting with a(2), this is row j = 1 in Table 3 (p. 176) in Wang et al. (2003). This is also corroborated by the title of the table: "The numbers f_{ij} of stereo isomers of acyclic saturated compounds consisting of C, O, and H, C_i H_{2i+2} O_j". Such a claim, if true, can probably be proved by using Eqs. (5), (6), and (7) on pp. 175-176 of the paper. - _Petros Hadjicostas_, Jul 24 2019
%D A005957 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A005957 R. C. Read, <a href="/A000598/a000598.pdf">The Enumeration of Acyclic Chemical Compounds</a>, pp. 25-61 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976. [Annotated scanned copy] See p. 44.
%H A005957 Jianji Wang, Ruxiong Li, and Shen Wang, <a href="https://doi.org/10.1023/A:1024745122889">Enumeration of isomers of acyclic saturated hydroxyl ethers</a>, Journal of Mathematical Chemistry 33 (2003), 171-179.
%F A005957 G.f.: (1/2)*x*(B^2(x)+B(x^2)) where B(x) is the g.f. for A000625. - _Sean A. Irvine_, Nov 12 2016
%K A005957 nonn
%O A005957 1,3
%A A005957 _N. J. A. Sloane_
%E A005957 a(23) corrected, title improved, and more terms from _Sean A. Irvine_, Nov 12 2016