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 A093835 #10 May 07 2019 11:12:04
%S A093835 0,1,2,9,20,55,126,301,680,1539,3410,7513,16380,35503,76454,163845,
%T A093835 349520,742747,1572858,3320497,6990500,14680071,30758222,64312669,
%U A093835 134217720,279620275,581610146,1207959561,2505397580,5189752159
%N A093835 n*Jacobsthal(n).
%C A093835 Convolution of Jacobsthal numbers A001045 and modified Jacobsthal-Lucas numbers (in A014551, change the leading 2 to a 1).
%H A093835 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,3,-4,-4).
%F A093835 G.f.: x(1+2x^2)/(1-x-2x^2)^2; a(n)=n2^n/3-n(-1)^n/3.
%F A093835 a(n) = n*A001045(n). - _R. J. Mathar_, May 07 2019
%t A093835 LinearRecurrence[{2,3,-4,-4},{0,1,2,9},30] (* _Harvey P. Dale_, Jun 17 2017 *)
%Y A093835 Cf. A023607.
%K A093835 nonn,easy
%O A093835 0,3
%A A093835 _Paul Barry_, Apr 20 2004