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 A257068 #6 Jun 02 2025 11:46:49 %S A257068 4,33,284,729,4096,7353,20249,37893,80545,117649,262144,354756,612724, %T A257068 882855,1398784,1771561,2985984,3661425,5323339,6888321,9595049, %U A257068 11390625,16777216,19566096,26006996,31736589,41119756,47045881,64000000,72407025 %N A257068 Number of length 6 1..(n+1) arrays with every leading partial sum divisible by 2 or 3. %C A257068 Row 6 of A257062 %H A257068 R. H. Hardin, <a href="/A257068/b257068.txt">Table of n, a(n) for n = 1..210</a> %F A257068 Empirical: a(n) = a(n-1) +6*a(n-6) -6*a(n-7) -15*a(n-12) +15*a(n-13) +20*a(n-18) -20*a(n-19) -15*a(n-24) +15*a(n-25) +6*a(n-30) -6*a(n-31) -a(n-36) +a(n-37) %F A257068 Empirical for n mod 6 = 0: a(n) = (64/729)*n^6 + (80/243)*n^5 + (40/81)*n^4 + (7/27)*n^3 + (1/36)*n^2 %F A257068 Empirical for n mod 6 = 1: a(n) = (64/729)*n^6 + (104/243)*n^5 + (26/27)*n^4 + (6515/5832)*n^3 + (1181/1944)*n^2 + (161/648)*n + (3197/5832) %F A257068 Empirical for n mod 6 = 2: a(n) = (64/729)*n^6 + (88/243)*n^5 + (2/3)*n^4 + (2917/5832)*n^3 + (337/972)*n^2 + (50/81)*n - (1091/729) %F A257068 Empirical for n mod 6 = 3: a(n) = (64/729)*n^6 + (112/243)*n^5 + (8/9)*n^4 + (29/27)*n^3 + (25/36)*n^2 + (1/6)*n + (1/4) %F A257068 Empirical for n mod 6 = 4: a(n) = (64/729)*n^6 + (64/243)*n^5 + (80/243)*n^4 + (160/729)*n^3 + (20/243)*n^2 + (4/243)*n + (1/729) %F A257068 Empirical for n mod 6 = 5: a(n) = (64/729)*n^6 + (128/243)*n^5 + (320/243)*n^4 + (1280/729)*n^3 + (320/243)*n^2 + (128/243)*n + (64/729) %e A257068 Some solutions for n=4 %e A257068 ..4....2....4....2....2....3....3....2....3....4....2....2....3....2....3....3 %e A257068 ..5....4....2....4....1....3....3....2....3....5....1....1....5....4....3....5 %e A257068 ..5....2....4....2....3....3....4....4....3....1....3....5....1....2....2....1 %e A257068 ..2....2....5....2....3....3....2....4....1....4....4....2....5....4....4....3 %e A257068 ..5....5....1....2....1....3....4....4....2....1....4....4....2....4....3....2 %e A257068 ..5....1....4....2....2....3....5....2....3....5....4....4....4....4....1....1 %Y A257068 Cf. A257062 %K A257068 nonn %O A257068 1,1 %A A257068 _R. H. Hardin_, Apr 15 2015