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 A054773 #11 May 12 2021 10:12:57 %S A054773 1,4,36,204,980,3876,13596,42636,122666,326876,817388,1931540,4346404, %T A054773 9360540,19390548,38779380,75136675,141430680,259292440,463991880, %U A054773 811990680,1391975640,2341057896,3867821640,6285222804,10056336264 %N A054773 Number of nonnegative integer 4 X 4 matrices with sum of elements equal to n, up to rotational symmetry. %H A054773 Andrew Howroyd, <a href="/A054773/b054773.txt">Table of n, a(n) for n = 0..1000</a> %F A054773 G.f.: (x^16 - 4*x^15 + 28*x^14 - 12*x^13 + 76*x^12 + 60*x^11 + 196*x^10 - 44*x^9 + 422*x^8 - 44*x^7 + 196*x^6 + 60*x^5 + 76*x^4 - 12*x^3 + 28*x^2 - 4*x + 1)/ ((x - 1)^16*(x + 1)^8*(x^2 + 1)^4). %Y A054773 Row n=4 of A343874. %Y A054773 Cf. A008610. %K A054773 nonn %O A054773 0,2 %A A054773 _Vladeta Jovovic_, May 19 2000