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 A090284 #13 Mar 18 2017 09:55:46 %S A090284 4,3,2,1,1,2,3,4,3,4,4,3,2,1,1,2,2,1,1,2,3,4,4,3,4,3,2,1,1,2,3,4,3,4, %T A090284 4,3,2,1,1,2,2,1,1,2,3,4,4,3,4,3,2,1,1,2,3,4,3,4,4,3,2,1,1,2,2,1,1,2, %U A090284 3,4,4,3,4,3,2,1,1,2,3,4,3,4,4,3,2,1,1,2,2,1,1,2,3,4,4,3,4,3,2 %N A090284 "Plain Bob Minimus" in bell-ringing is a sequence of permutations p_1=(1,2,3,4), p_2=(2,1,4,3), .. which runs through all permutations of {1,2,3,4} with period 24; sequence gives position of bell 4 (the tenor bell) in n-th permutation. %H A090284 David Joyner, <a href="http://www.usna.edu/Users/math/wdj/book/node158.html">Application: Bell Ringing</a> %H A090284 <a href="/index/Rec#order_21">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, 0, -1, 1, 0, 0, -1, 1, 0, 0, -1, 1, 0, 0, -1, 1, 0, 0, -1, 1). %H A090284 <a href="/index/Be#bell_ringing">Index entries for sequences related to bell ringing</a> %F A090284 Period 24. %F A090284 From _Chai Wah Wu_, Jul 17 2016: (Start) %F A090284 a(n) = a(n-1) - a(n-4) + a(n-5) - a(n-8) + a(n-9) - a(n-12) + a(n-13) - a(n-16) + a(n-17) - a(n-20) + a(n-21) for n > 21. %F A090284 G.f.: x*(-3*x^20 - x^19 + x^17 - 2*x^16 - 2*x^12 + x^11 - x^9 - 3*x^8 - 4*x^4 + x^3 + x^2 + x - 4)/((x - 1)*(x^4 + 1)*(x^2 - x + 1)*(x^2 + x + 1)*(x^4 - x^2 + 1)*(x^8 - x^4 + 1)). (End) %Y A090284 Cf. A090277-A090283. %K A090284 nonn %O A090284 1,1 %A A090284 _N. J. A. Sloane_, Jan 24 2004