%I #16 Sep 08 2022 08:45:54

%S 5,35,107,197,341,491,707,917,1205,1475,1835,2165,2597,2987,3491,3941,

%T 4517,5027,5675,6245,6965,7595,8387,9077,9941,10691,11627,12437,13445,

%U 14315,15395,16325,17477,18467,19691,20741,22037,23147,24515

%N Positive integers of the form (6*m^2 + 1)/11.

%C Here m = (11*(2*n-1) - (-1)^n)/4 for n > 0.

%H B. Berselli, <a href="/A179337/b179337.txt">Table of n, a(n) for n = 1..10000</a>.

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-2,-1,1).

%F a(n) = (66*n*(n-1) - 3*(2*n-1)*(-1)^n + 17)/4.

%F G.f.: x*(5 + 30*x + 62*x^2 + 30*x^3 + 5*x^4)/((1+x)^2*(1-x)^3).

%F a(n) = a(-n+1) = a(n-1) + 2*a(n-2) - 2*a(n-3) - a(n-4) + a(n-5).

%t LinearRecurrence[{1,2,-2,-1,1},{5,35,107,197,341},40] (* _Vincenzo Librandi_, Nov 16 2011 *)

%o (Magma) [(66*n*(n-1)-3*(2*n-1)*(-1)^n+17)/4: n in [1..40]]; // _Vincenzo Librandi_, Nov 16 2011

%Y Cf. A113338, A179088, A179338, A179339, A179370.

%K nonn,easy

%O 1,1

%A _Bruno Berselli_, Jul 11 2010