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 A131326 #12 Jul 12 2017 07:47:22 %S A131326 1,3,4,9,13,24,37,63,100,165,265,432,697,1131,1828,2961,4789,7752, %T A131326 12541,20295,32836,53133,85969,139104,225073,364179,589252,953433, %U A131326 1542685,2496120,4038805,6534927,10573732,17108661,27682393,44791056,72473449,117264507 %N A131326 Row sums of A131325. %H A131326 Colin Barker, <a href="/A131326/b131326.txt">Table of n, a(n) for n = 0..1000</a> %H A131326 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,-1,-1). %F A131326 a(n) = A062114(n+1)+A052952(n-1). %F A131326 G.f. ( 1+2*x-x^2 ) / ( (x-1)*(1+x)*(x^2+x-1) ). - _R. J. Mathar_, Aug 12 2012 %F A131326 a(n) = 3*Fibonacci(n+1)-2 if n even, a(n) = 3*Fibonacci(n+1) if n odd. - _R. J. Mathar_, Aug 12 2012 %F A131326 From _Colin Barker_, Jul 12 2017: (Start) %F A131326 a(n) = (3*2^(-n-1)*((1 + sqrt(5))^(n+1) - (1 - sqrt(5))^(n+1))) / sqrt(5) - 2 for n even. %F A131326 a(n) = (3*2^(-n-1)*((1 + sqrt(5))^(n+1) - (1 - sqrt(5))^(n+1))) / sqrt(5) for n odd. %F A131326 a(n) = a(n-1) + 2*a(n-2) - a(n-3) - a(n-4) for n>3. %F A131326 (End) %o A131326 (PARI) Vec((1+2*x-x^2) / ((x-1)*(1+x)*(x^2+x-1)) + O(x^50)) \\ _Colin Barker_, Jul 12 2017 %Y A131326 Cf. A131325, A049310, A062114, A052952, A022086. %K A131326 nonn,easy %O A131326 0,2 %A A131326 _Gary W. Adamson_, Jun 28 2007