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 A165025 #17 Jun 02 2017 00:44:27 %S A165025 1,0,1,2,1,3,1,4,3,5,4,8,5,10,8,12,10,16,12,19,16,22,19,27,22,31,27, %T A165025 35,31,41,35,46,41,51,46,58,51,64,58,70,64,78,70,85,78,92,85,101,92, %U A165025 109,101,117,109,127,117,136,127,145,136,156,145,166,156,176,166,188,176 %N A165025 Number of cycles of n-digit numbers (including fixed points) under the base-4 Kaprekar map A165012. %H A165025 Joseph Myers, <a href="/A165025/b165025.txt">Table of n, a(n) for n=1..200</a> %H A165025 H. Hanslik, E. Hetmaniok, I. Sobstyl, et al., <a href="http://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-aeb2e2a6-99ca-4268-8f6b-a947b9c04da9">Orbits of the Kaprekar's transformations-some introductory facts</a>, Zeszyty Naukowe Politechniki Śląskiej, Seria: Matematyka Stosowana z. 5, Nr kol. 1945; 2015. %H A165025 <a href="/index/K#Kaprekar_map">Index entries for the Kaprekar map</a> %F A165025 Conjectures from _Colin Barker_, Jun 01 2017: (Start) %F A165025 G.f.: x*(1 - x^2 + x^3 - 2*x^6 + 3*x^8 - x^10) / ((1 - x)^3*(1 + x)^2*(1 + x + x^2)). %F A165025 a(n) = 2*a(n-2) + a(n-3) - a(n-4) - 2*a(n-5) + a(n-7) for n>7. %F A165025 (End) %Y A165025 Cf. A165012, A165017, A165026, A165027. %Y A165025 In other bases: A004526 (base 2, adjusted to start 1, 0, 0, 1, 1, ...), A165006 (base 3), A165045 (base 5), A165064 (base 6), A165084 (base 7), A165103 (base 8), A165123 (base 9), A164731 (base 10). %K A165025 base,nonn %O A165025 1,4 %A A165025 _Joseph Myers_, Sep 04 2009