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 A183881 #7 Jul 22 2025 09:16:22 %S A183881 1,1,1231,32521,424537,4079713,33702403,257404033,1885866973, %T A183881 13515603289,95750388631,674299155193,4734193668289,33187816266097, %U A183881 232479450595819,1627911123290065,11397233380815013,79786797746740777,558527947985495935 %N A183881 Number of arrangements of n+2 numbers in 0..6 with each number being the sum mod 7 of two others. %C A183881 Column 6 of A183884 %H A183881 R. H. Hardin, <a href="/A183881/b183881.txt">Table of n, a(n) for n = 1..80</a> %e A183881 Some solutions for n=3 %e A183881 ..1....2....3....1....5....4....4....3....1....2....2....5....6....2....1....1 %e A183881 ..3....0....2....3....2....5....6....5....5....5....6....3....1....1....3....4 %e A183881 ..5....0....1....6....5....3....3....1....2....4....1....6....5....6....6....5 %e A183881 ..2....0....3....2....0....2....5....5....3....3....5....2....2....4....3....2 %e A183881 ..4....2....6....4....2....1....1....4....4....1....3....1....4....5....2....6 %K A183881 nonn %O A183881 1,3 %A A183881 _R. H. Hardin_ Jan 07 2011