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 A213770 #20 Sep 08 2022 08:46:02 %S A213770 1,7,23,58,126,250,467,837,1457,2484,4172,6932,11429,18739,30603, %T A213770 49838,81002,131470,213175,345425,559461,905832,1466328,2373288, %U A213770 3840841,6215455,10057727,16274722,26334102,42610594,68946587,111559197 %N A213770 Antidiagonal sums of the convolution array A213768. %H A213770 Clark Kimberling, <a href="/A213770/b213770.txt">Table of n, a(n) for n = 1..1000</a> %H A213770 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,1,2,-1). %F A213770 a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5). %F A213770 G.f.: f(x)/g(x), where f(x) = x*(1 + 3*x) and g(x) = (1 - x - x^2)(1 - x)^3. %F A213770 a(n) = 2*Fibonacci(n+6) + Lucas(n+4) - n*(2*n + 11) - 23. - _Ehren Metcalfe_, Jul 08 2019 %t A213770 (See A213768.) %o A213770 (Magma) [2*Fibonacci(n+6)+Lucas(n+4)-n*(2*n+11)-23: n in [1..35]]; // _Vincenzo Librandi_, Jul 09 2019 %Y A213770 Cf. A213768, A213500. %K A213770 nonn,easy %O A213770 1,2 %A A213770 _Clark Kimberling_, Jun 21 2012