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 A185278 #19 Sep 06 2018 14:55:02 %S A185278 1,1,2,1,2,2,2,2,3,2,4,2,3,3,5,2,5,3,4,3,6,4,6,4,5,4,8,3,8,5,6,5,7,4, %T A185278 10,5,7,6,11,4,11,6,7,6,12,6,11,6,9,7,14,5,11,8,10,8,15,6,16,8,10,9, %U A185278 14,6,17,9,12,7,18,8,19,10,11,10,16,7,20,10,14,11,21,8,18,11,15,12,23,7,19,12,16,12,19,10,25,11,16,11 %N A185278 Number of isomorphism classes of generalized Petersen graphs G(n,k) on 2n vertices with gcd(n,k) = 1. %H A185278 Robert Israel, <a href="/A185278/b185278.txt">Table of n, a(n) for n = 3..10000</a> %H A185278 Marko Petkovsek and Helena Zakrajsek, <a href="http://amc-journal.eu/index.php/amc/article/view/113">Enumeration of I-graphs: Burnside does it again</a>, Ars Mathematica Contemporanea, 2 (2009) 241-262. %H A185278 A. Steimle and W. Staton, <a href="http://dx.doi.org/10.1016/j.disc.2007.12.074">The isomorphism classes of the generalized Petersen graphs</a>, Discrete Math. 309 (2009), 231-237. %F A185278 a(n) = (A000010(n) + A060594(n) + A000089(n))/4. %p A185278 # using functions A060594 and A000089 as defined in those sequences %p A185278 f:= n -> (numtheory:-phi(n)+A060594(n)+A000089(n))/4: %p A185278 map(f, [$3..100]); # _Robert Israel_, Sep 06 2018 %Y A185278 Cf. A000010, A000089, A060594. %K A185278 nonn,look %O A185278 3,3 %A A185278 _N. J. A. Sloane_, Feb 19 2011