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 A246737 #6 Jul 23 2025 11:31:58 %S A246737 2,12,2,124,16,2,424,260,22,2,1566,1096,548,30,2,3876,5430,2884,1156, %T A246737 40,2,9368,15960,18966,7612,2436,52,2,18768,47432,66378,66294,19992, %U A246737 5132,68,2,36250,109552,241544,276762,231414,52112,10812,90,2,63100,246890 %N A246737 T(n,k)=Number of length n+4 0..k arrays with no pair in any consecutive five terms totalling exactly k. %C A246737 Table starts %C A246737 .2..12....124.....424......1566.......3876........9368........18768 %C A246737 .2..16....260....1096......5430......15960.......47432.......109552 %C A246737 .2..22....548....2884.....18966......66378......241544.......643048 %C A246737 .2..30...1156....7612.....66294.....276762.....1231304......3780600 %C A246737 .2..40...2436...19992....231414....1152576.....6272072.....22219408 %C A246737 .2..52...5132...52112....807630....4791012....31944440....130526848 %C A246737 .2..68..10812..135776...2818830...19906740...162700376....766650656 %C A246737 .2..90..22780..354428...9838974...82727094...828690200...4502888280 %C A246737 .2.120..47996..926912..34342350..343911336..4220813912..26449024896 %C A246737 .2.160.101124.2426008.119869158.1430080296.21498069128.155366381200 %H A246737 R. H. Hardin, <a href="/A246737/b246737.txt">Table of n, a(n) for n = 1..1661</a> %F A246737 Empirical for column k: %F A246737 k=1: a(n) = a(n-1) %F A246737 k=2: a(n) = a(n-1) +a(n-5) %F A246737 k=3: a(n) = 2*a(n-1) +a(n-4) %F A246737 k=4: [order 16] %F A246737 k=5: a(n) = 3*a(n-1) +a(n-2) +a(n-3) +5*a(n-4) +a(n-5) -a(n-6) -a(n-7) %F A246737 k=6: [order 23] %F A246737 k=7: a(n) = 4*a(n-1) +4*a(n-2) +4*a(n-3) +18*a(n-4) +12*a(n-5) -4*a(n-7) -a(n-8) %F A246737 k=8: [order 24] %F A246737 k=9: a(n) = 6*a(n-1) +4*a(n-2) +6*a(n-3) +38*a(n-4) +18*a(n-5) -6*a(n-7) -a(n-8) %F A246737 Empirical for row n: %F A246737 n=1: a(n) = 3*a(n-1) -8*a(n-3) +6*a(n-4) +6*a(n-5) -8*a(n-6) +3*a(n-8) -a(n-9) %F A246737 n=2: [order 11] %F A246737 n=3: [order 13] %F A246737 n=4: [order 15] %F A246737 n=5: [order 17] %F A246737 n=6: [order 19] %F A246737 n=7: [order 21] %e A246737 Some solutions for n=4 k=4 %e A246737 ..3....4....3....1....1....0....2....1....1....0....2....3....2....4....0....0 %e A246737 ..3....1....2....4....4....1....0....4....1....0....4....4....4....3....2....0 %e A246737 ..3....1....3....1....2....2....1....2....2....1....3....2....1....4....0....0 %e A246737 ..4....1....4....4....1....1....1....1....4....0....3....3....4....4....0....0 %e A246737 ..4....4....4....1....4....0....0....1....4....0....3....4....4....4....1....0 %e A246737 ..4....1....4....1....1....0....0....1....1....2....3....3....1....3....0....2 %e A246737 ..3....2....2....2....4....1....2....0....1....0....4....3....1....3....2....1 %e A246737 ..4....4....1....1....1....1....0....2....2....1....3....4....2....3....0....0 %Y A246737 Column 2 is A174469(n+18) %K A246737 nonn,tabl %O A246737 1,1 %A A246737 _R. H. Hardin_, Sep 02 2014