%I #8 Feb 11 2017 16:03:20

%S 1,12,99,112,399,312,899,612,1599,1012,2499,1512,3599,2112,4899,2812,

%T 6399,3612,8099,4512,9999,5512,12099,6612,14399,7812,16899,9112,19599,

%U 10512,22499,12012,25599,13612,28899,15312,32399,17112,36099,19012,39999,21012

%N Least common multiple of 5*n+1 and 5*n-1.

%H Colin Barker, <a href="/A282285/b282285.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,3,0,-3,0,1).

%F a(n) = 25*n^2-1 for n>0 and even.

%F a(n) = (25*n^2-1)/2 for n odd.

%F a(n) = 3*a(n-2) - 3*a(n-4) + a(n-6) for n>6.

%F 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 (PARI) vector(60, n, n--; lcm(5*n+1, 5*n-1))

%o (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 Cf. A000466, A136017, A141759, A282284, A282286.

%K nonn,easy

%O 0,2

%A _Colin Barker_, Feb 11 2017