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 A277636 #34 Jan 02 2017 20:35:22 %S A277636 1,343,6859,50653,226981,753571,2048383,4826809,10218313,19902511, %T A277636 36264691,62570773,103161709,163667323,251239591,374805361,545338513, %U A277636 776151559,1083206683,1485446221,2005142581,2668267603,3504881359,4549540393,5841725401,7426288351 %N A277636 Number of 3 X 3 matrices having all elements in {0,...,n} with determinant = permanent. %C A277636 a(n) is a perfect cube. %H A277636 Indranil Ghosh, <a href="/A277636/b277636.txt">Table of n, a(n) for n = 0..100</a> %H A277636 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-7,1). %F A277636 a(n) = A003215(n-1)^3. %F A277636 a(n) = (3*n^2 - 3*n + 1)^3. %F A277636 G.f.: (1 + 336*x + 4479*x^2 + 9808*x^3 + 4479*x^4 + 336*x^5 + x^6) / (1 - x)^7. - _Colin Barker_, Jan 02 2017 %o A277636 (Python) %o A277636 def a(n): %o A277636 return 27*n**6-81*n**5+108*n**4-81*n**3+36*n**2-9*n+1 %o A277636 (PARI) Vec((1 + 336*x + 4479*x^2 + 9808*x^3 + 4479*x^4 + 336*x^5 + x^6) / (1 - x)^7 + O(x^30)) \\ _Colin Barker_, Jan 02 2017 %Y A277636 Cf. A059976 (Number of 3 X 3 singular matrices with all elements in {0,...,n}) %Y A277636 Cf. A015237 (Number of 2 X 2 matrices with all elements in {0,...,n} with determinant = permanent ) %Y A277636 Cf. A003215. %K A277636 nonn,easy %O A277636 0,2 %A A277636 _Indranil Ghosh_, Jan 02 2017