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 A282285 #8 Feb 11 2017 16:03:20 %S A282285 1,12,99,112,399,312,899,612,1599,1012,2499,1512,3599,2112,4899,2812, %T A282285 6399,3612,8099,4512,9999,5512,12099,6612,14399,7812,16899,9112,19599, %U A282285 10512,22499,12012,25599,13612,28899,15312,32399,17112,36099,19012,39999,21012 %N A282285 Least common multiple of 5*n+1 and 5*n-1. %H A282285 Colin Barker, <a href="/A282285/b282285.txt">Table of n, a(n) for n = 0..1000</a> %H A282285 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,3,0,-3,0,1). %F A282285 a(n) = 25*n^2-1 for n>0 and even. %F A282285 a(n) = (25*n^2-1)/2 for n odd. %F A282285 a(n) = 3*a(n-2) - 3*a(n-4) + a(n-6) for n>6. %F A282285 G.f.: (1+12*x+96*x^2+76*x^3+105*x^4+12*x^5-2*x^6) / ((1-x)^3*(1+x)^3). %o A282285 (PARI) vector(60, n, n--; lcm(5*n+1, 5*n-1)) %o A282285 (PARI) Vec((1+12*x+96*x^2+76*x^3+105*x^4+12*x^5-2*x^6) / ((1-x)^3*(1+x)^3) + O(x^60)) %Y A282285 Cf. A000466, A136017, A141759, A282284, A282286. %K A282285 nonn,easy %O A282285 0,2 %A A282285 _Colin Barker_, Feb 11 2017