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 A183903 #6 Jul 22 2025 09:17:41 %S A183903 1,9,242,1866,6503,15973,33236,62678,110487,185231,298538,465912, %T A183903 707702,1050242,1527181,2181023,3064898,4244586,5800817,7831871, %U A183903 10456503 %N A183903 Number of nondecreasing arrangements of n+3 numbers in 0..8 with each number being the sum mod 9 of three others. %C A183903 Column 8 of A183904 %F A183903 Empirical: a(n) = (1/40320)*n^8 + (1/672)*n^7 + (37/960)*n^6 + (9/16)*n^5 + (9709/1920)*n^4 + (917/32)*n^3 + (14159/10080)*n^2 - (119065/168)*n + 801 for n>5 %e A183903 All solutions for n=2 %e A183903 ..0....0....0....0....0....0....0....1....2 %e A183903 ..0....0....3....0....0....3....0....3....5 %e A183903 ..3....3....6....3....6....3....0....3....6 %e A183903 ..6....3....6....3....6....3....0....4....6 %e A183903 ..6....3....6....6....6....6....0....7....8 %K A183903 nonn %O A183903 1,2 %A A183903 _R. H. Hardin_ Jan 07 2011