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 A259017 #26 Aug 01 2024 14:12:07 %S A259017 0,1,172,17041,1382400,104454120,7801139200,593322510704, %T A259017 46672464052224,3827977546598400,328664453612830720, %U A259017 29590252898580000000,2794588822832496508928,276747699113763664091136,28712738456619366481920000,3117500646133634877355274240,353783948741967872000000000000 %N A259017 Number of fixed tree polycubes of size n that are proper in n-4 dimensions. %H A259017 Colin Barker, <a href="/A259017/b259017.txt">Table of n, a(n) for n = 4..351</a> %H A259017 G. Barequet and M. Shalah, <a href="https://www.youtube.com/watch?v=ojNDm8qKr9A">Automatic Proofs for Formulae Enumerating Proper Polycubes</a>. %H A259017 G. Barequet and M. Shalah, <a href="http://dx.doi.org/10.4230/LIPIcs.SOCG.2015.19">Automatic Proofs for Formulae Enumerating Proper Polycubes</a>. %F A259017 a(n) = 2^(n-7)*n^(n-9)*(n-4)*(8*n^8 - 140*n^7 + 1010*n^6 - 3913*n^5 + 9201*n^4 - 15662*n^3 + 34500*n^2 - 120552*n + 221760)/6. %o A259017 (PARI) a(n) = 2^(n-7) * n^(n-9) * (n-4) * (8*n^8-140*n^7+1010*n^6 -3913*n^5 +9201*n^4-15662*n^3+34500*n^2-120552*n +221760)/6 \\ _Colin Barker_, Jun 16 2015 %o A259017 (Magma) [2^(n-7)*n^(n-9)*(n-4)*(8*n^8 - 140*n^7 + 1010*n^6 - 3913*n^5 + 9201*n^4 - 15662*n^3 + 34500*n^2 - 120552*n + 221760)/6: n in [4..20]]; // _Vincenzo Librandi_, Jun 20 2015 %Y A259017 A259015 gives the total number of fixed polycubes (not necessarily trees) proper in n-4 dimensions. %K A259017 nonn,easy %O A259017 4,3 %A A259017 _Mira Shalah_, Jun 16 2015