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 A074453 #12 Oct 25 2020 02:39:05
%S A074453 6,1,-3,1,17,16,-15,-13,81,127,-58,-175,329,885,-31,-1424,833,5543,
%T A074453 2181,-9233,-2298,31025,27893,-49495,-54879,150416,245697,-204965,
%U A074453 -526887,570895,1801670,-407711,-3882303,946397,11542929,3442672,-24121039,-10317745,64959629,56727711,-127083514
%N A074453 Sum of determinants of 2nd order principal minors of powers of inverse of the matrix ((1,1,0,0),(1,0,1,0),(1,0,0,1),(1,0,0,0)).
%C A074453 a(n) is the reflected (A074058) sequence of sequence A074193.
%H A074453 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (1, -2, 2, 2, 1, 1).
%F A074453 a(n)=a(n-1)-2a(n-2)+2a(n-3)+2a(n-4)+a(n-5)+a(n-6).
%F A074453 G.f.: (6-5x+8x^2-6x^3-4x^4-x^5)/(1-x+2x^2-2x^3-2x^4-x^5-x^6).
%F A074453 abs(a(n)) = abs(A074193(n)). - _Joerg Arndt_, Oct 22 2020
%t A074453 CoefficientList[Series[(6-5*x+8*x^2-6*x^3-4*x^4-x^5)/(1-x+2*x^2-2*x^3-2*x^4-x^5-x^6), {x, 0, 40}], x]
%t A074453 LinearRecurrence[{1,-2,2,2,1,1},{6,1,-3,1,17,16},50] (* _Harvey P. Dale_, Mar 16 2012 *)
%Y A074453 Cf. A073817, A073937, A074058, A074081, A074193.
%K A074453 easy,sign
%O A074453 0,1
%A A074453 Mario Catalani (mario.catalani(AT)unito.it), Aug 22 2002