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 A386553 #20 Aug 03 2025 18:07:20 %S A386553 1,4,22,139,779,3455,12507,37303,92968,195963,352433,544382,725612, %T A386553 837184,837184,725612,544382,352433,195963,92968,37303,12507,3455,779, %U A386553 139,22,4,1 %N A386553 Number of 2-colorings of an 3 X 3 X 3 grid, up to rotational symmetry, by the number of black cells. %C A386553 This sequence is finite, having 3^3+1 terms. The cycle index Z(C) of the permutation group C of the rotations of the cube acting on the cells is given by 1/24 (a[1]^27 + 8 * a[1]^3 * a[3]^8 + 9 * a[1]^3 * a[2]^12 + 6 * a[1]^3*a[4]^6). %D A386553 F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, 1973, page 35. %F A386553 a(n) = [z^n] Z(C; 1+z). %Y A386553 Cf. A334616, A386554, A386555, A386556. %K A386553 nonn,fini,full %O A386553 0,2 %A A386553 _Marko Riedel_, Jul 25 2025