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 A250277 #8 Jul 23 2025 12:16:34 %S A250277 2,3,4,4,11,8,5,20,27,16,6,33,52,79,32,7,48,89,240,255,64,8,67,140, %T A250277 581,984,843,128,9,88,207,1132,2909,4412,2763,256,10,113,288,1991, %U A250277 6732,17885,20252,8903,512,11,140,389,3156,14003,51884,107387,91808,28215,1024,12 %N A250277 T(n,k)=Number of length n+1 0..k arrays with the sum of the squares of adjacent differences multiplied by some arrangement of +-1 equal to zero. %C A250277 Table starts %C A250277 ....2.....3.......4........5.........6.........7..........8...........9 %C A250277 ....4....11......20.......33........48........67.........88.........113 %C A250277 ....8....27......52.......89.......140.......207........288.........389 %C A250277 ...16....79.....240......581......1132......1991.......3156........4841 %C A250277 ...32...255.....984.....2909......6732.....14003......25964.......45303 %C A250277 ...64...843....4412....17885.....51884....130335.....281552......564985 %C A250277 ..128..2763...20252...107387....381812...1154141....2908232.....6704631 %C A250277 ..256..8903...91808...636197...2783500..10172515...30143732....80256473 %C A250277 ..512.28215..406748..3664311..19762916..86975297..301550620...925066871 %C A250277 .1024.88195.1759740.20397261.135821156.715749943.2901853512.10244309701 %H A250277 R. H. Hardin, <a href="/A250277/b250277.txt">Table of n, a(n) for n = 1..181</a> %F A250277 Empirical for column k: %F A250277 k=1: a(n) = 2*a(n-1) %F A250277 k=2: a(n) = 9*a(n-1) -31*a(n-2) +51*a(n-3) -40*a(n-4) +12*a(n-5) for n>6 %F A250277 k=3: [order 15] for n>18 %F A250277 Empirical for row n: %F A250277 n=1: a(n) = n + 1 %F A250277 n=2: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4); also a quadratic polynomial plus a constant quasipolynomial with period 2 %e A250277 Some solutions for n=6 k=4 %e A250277 ..4....0....0....1....3....3....4....3....3....1....2....0....4....1....3....3 %e A250277 ..2....2....0....1....1....3....2....3....2....4....3....3....4....3....2....4 %e A250277 ..4....2....2....4....2....3....0....3....4....4....0....2....4....2....2....4 %e A250277 ..2....1....4....4....1....3....4....1....2....1....2....4....2....3....1....2 %e A250277 ..2....2....4....2....1....1....4....0....1....2....4....3....1....1....1....4 %e A250277 ..2....3....2....1....1....3....2....1....2....1....3....4....2....1....0....0 %e A250277 ..4....2....0....3....3....3....0....3....3....1....0....2....4....1....1....3 %Y A250277 Column 1 is A000079 %Y A250277 Row 2 is A212959 %K A250277 nonn,tabl %O A250277 1,1 %A A250277 _R. H. Hardin_, Nov 16 2014