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 A131949 #17 Nov 05 2017 07:47:33
%S A131949 1,6,16,32,56,92,148,240,400,692,1244,2312,4408,8556,16804,33248,
%T A131949 66080,131684,262828,525048,1049416,2098076,4195316,8389712,16778416,
%U A131949 33555732,67110268,134219240,268437080,536872652,1073743684,2147485632,4294969408,8589936836
%N A131949 Row sums of triangle A131948.
%H A131949 Colin Barker, <a href="/A131949/b131949.txt">Table of n, a(n) for n = 0..1000</a>
%H A131949 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (5,-9,7,-2).
%F A131949 Binomial transform of (1, 5, 5, 1, 1, 1, ...).
%F A131949 G.f.: 1-2*x*(-3+7*x-3*x^2+x^3) / ( (2*x-1)*(x-1)^3 ). - _R. J. Mathar_, Apr 04 2012
%F A131949 From _Colin Barker_, Nov 04 2017: (Start)
%F A131949 a(n) = 2^n + 2*n + 2*n^2.
%F A131949 a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4) for n > 3.
%F A131949 (End)
%e A131949 a(3) = 32 = sum of row 3 terms, triangle A131948: (7 + 9 + 9 + 7).
%e A131949 a(3) = 32 = (1, 3, 3, 1) dot (1, 5, 5, 1) = (1 + 15 + 15 + 1).
%t A131949 LinearRecurrence[{5,-9,7,-2},{1,6,16,32},30] (* _Harvey P. Dale_, Feb 24 2016 *)
%o A131949 (PARI) Vec((1 + x - 5*x^2 - x^3) / ((1 - x)^3*(1 - 2*x)) + O(x^40)) \\ _Colin Barker_, Nov 04 2017
%Y A131949 Cf. A131948.
%K A131949 nonn,easy
%O A131949 0,2
%A A131949 _Gary W. Adamson_, Jul 30 2007