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 A083672 #16 Feb 07 2023 15:12:51
%S A083672 1,1,9,25,97,321,1097,3641,12033,39361,127945,413337,1328609,4251521,
%T A083672 13551753,43046713,136314625,430467201,1355971721,4261625369,
%U A083672 13366006881,41841412801,130754415049,407953774905,1270932914177
%N A083672 Binomial transform of 1,8,48,256,1280,6144,... (cf. A002697).
%H A083672 Harvey P. Dale, <a href="/A083672/b083672.txt">Table of n, a(n) for n = 0..1000</a>
%H A083672 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,2,-12,-9).
%F A083672 a(n) = (1/6)*((n + 3)*3^n + (3*n + 3)*(-1)^n).
%F A083672 O.g.f.: -(x - 1)^3/((-1 + 3*x)^2*(1 + x)^2). - _R. J. Mathar_, Apr 02 2008
%F A083672 E.g.f.: exp(x)*(cosh(2*x) + x*sinh(2*x)). - _Stefano Spezia_, Aug 04 2022
%t A083672 LinearRecurrence[{4,2,-12,-9},{1,1,9,25},30] (* _Harvey P. Dale_, Feb 07 2023 *)
%Y A083672 Cf. A002697, A045891.
%K A083672 easy,nonn
%O A083672 0,3
%A A083672 _Paul Barry_, May 02 2003