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 A008617 #33 Jul 08 2025 01:18:40
%S A008617 1,0,1,0,1,0,1,1,1,1,1,1,1,1,2,1,2,1,2,1,2,2,2,2,2,2,2,2,3,2,3,2,3,2,
%T A008617 3,3,3,3,3,3,3,3,4,3,4,3,4,3,4,4,4,4,4,4,4,4,5,4,5,4,5,4,5,5,5,5,5,5,
%U A008617 5,5,6,5,6,5,6,5,6,6
%N A008617 Expansion of 1/((1-x^2)(1-x^7)).
%C A008617 a(n) is the number of (n+9)-digit fixed points under the base-5 Kaprekar map A165032 (see A165036 for the list of fixed points). - _Joseph Myers_, Sep 04 2009
%C A008617 It appears that this is the number of partitions of 4*n that are 8-term arithmetic progressions. Further, it seems that a(n)=[n/2]-[3n/7]. - _John W. Layman_, Feb 21 2012
%D A008617 D. J. Benson, Polynomial Invariants of Finite Groups, Cambridge, 1993, p. 100.
%H A008617 Vincenzo Librandi, <a href="/A008617/b008617.txt">Table of n, a(n) for n = 0..1000</a>
%H A008617 INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=214">Encyclopedia of Combinatorial Structures 214</a>
%H A008617 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (0, 1, 0, 0, 0, 0, 1, 0, -1).
%F A008617 a(n) = floor((2*n+21+7*(-1)^n)/28). - _Tani Akinari_, May 19 2014
%t A008617 CoefficientList[Series[1 / ((1 - x^2) (1 - x^7)), {x, 0, 100}], x] (* _Vincenzo Librandi_, Jun 22 2013 *)
%t A008617 LinearRecurrence[{0,1,0,0,0,0,1,0,-1},{1,0,1,0,1,0,1,1,1},80] (* _Harvey P. Dale_, May 18 2018 *)
%K A008617 nonn,easy
%O A008617 0,15
%A A008617 _N. J. A. Sloane_
%E A008617 Typo in name fixed by _Vincenzo Librandi_, Jun 22 2013