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 A254533 #6 Jul 23 2025 14:46:22 %S A254533 2,3,8,20,50,126,329,956,2897,8341,23238,66544,194686,555838,1532445, %T A254533 4225095,12140873,36623429,112964359,345148105,1027400959,2988415841, %U A254533 8604041257,24715209608,70743541258,201532200098,575286723544 %N A254533 Number of length n 1..(2+2) arrays with no leading partial sum equal to a prime. %C A254533 Column 2 of A254539 %H A254533 R. H. Hardin, <a href="/A254533/b254533.txt">Table of n, a(n) for n = 1..210</a> %e A254533 Some solutions for n=4 %e A254533 ..4....1....4....4....4....4....4....4....1....1....1....1....4....4....4....1 %e A254533 ..2....3....4....4....2....4....4....2....3....3....3....3....2....2....4....3 %e A254533 ..3....4....1....4....2....4....2....4....4....2....2....4....2....2....1....2 %e A254533 ..3....1....3....3....2....2....4....4....4....4....3....2....4....1....1....2 %K A254533 nonn %O A254533 1,1 %A A254533 _R. H. Hardin_, Feb 01 2015