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 A248468 #6 Jul 23 2025 11:44:34 %S A248468 110,1152,43940,387488,2582406,11447368,44452660,139623544,400150926, %T A248468 1002628764,2352502608,5078891508,10430306882,20141675148,37480145240, %U A248468 66683720948,115148012058,192026426768,312626222120,495163608752 %N A248468 Number of length 7+2 0..n arrays with no three consecutive terms having the sum of any two elements equal to twice the third. %C A248468 Row 7 of A248461 %H A248468 R. H. Hardin, <a href="/A248468/b248468.txt">Table of n, a(n) for n = 1..210</a> %e A248468 Some solutions for n=3 %e A248468 ..0....2....2....1....3....1....0....0....2....1....0....3....2....1....1....3 %e A248468 ..0....2....3....3....1....0....0....3....3....3....3....1....2....3....0....1 %e A248468 ..1....3....3....3....0....3....3....3....0....3....1....1....0....0....1....0 %e A248468 ..1....0....0....0....0....2....1....1....2....2....3....3....2....3....1....3 %e A248468 ..3....2....0....1....3....0....0....3....3....2....3....1....0....3....3....2 %e A248468 ..0....3....3....1....2....2....0....1....0....1....2....3....3....0....0....3 %e A248468 ..1....3....0....0....0....0....2....0....0....2....2....1....3....1....3....0 %e A248468 ..0....2....1....3....3....2....0....0....2....1....0....3....2....1....0....1 %e A248468 ..0....3....1....3....0....0....3....3....0....2....3....3....2....3....0....1 %K A248468 nonn %O A248468 1,1 %A A248468 _R. H. Hardin_, Oct 06 2014