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 A213755 #18 Feb 19 2024 03:11:02 %S A213755 1,9,44,160,491,1355,3486,8546,20245,46773,106048,236980,523535, %T A213755 1145935,2489202,5372534,11532633,24639513,52426420,111146280, %U A213755 234877811,494924179,1040183174,2181033290,4563397341,9529452605 %N A213755 Antidiagonal sums of the convolution array A213753. %H A213755 Clark Kimberling, <a href="/A213755/b213755.txt">Table of n, a(n) for n = 1..1000</a> %H A213755 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (8,-26,44,-41,20,-4). %F A213755 a(n) = (1/6)*(84 - 21*2^(n+2) + 23*n + 9*n*2^(n+2) - 3*n^2 - 2*n^3). %F A213755 a(n) = 8*a(n-1) - 26*a(n-2) + 44*a(n-3) - 41*a(n-4) + 20*a(n-5) - 4*a(n-6). %F A213755 G.f.: f(x)/g(x), where f(x) = x*(1 + x - 2*x^2 - 2*x^3) and g(x) = (1 - x)^4 * (1 - 2*x)^2. %t A213755 (See A213753.) %Y A213755 Cf. A213753, A213500. %K A213755 nonn,easy %O A213755 1,2 %A A213755 _Clark Kimberling_, Jun 20 2012