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 A228458 #9 Jun 19 2025 21:28:35 %S A228458 6,36,161,581,1847,5615,17487,57303,194064,659418,2212695,7329603, %T A228458 24138450,79571792,263302273,873867641,2902730184,9635417630, %U A228458 31950864559,105883279595,350872561227,1163005850963,3855906404239,12785544028311 %N A228458 Number of arrays of maxima of three adjacent elements of some length n+2 0..5 array. %C A228458 Column 5 of A228461. %H A228458 R. H. Hardin, <a href="/A228458/b228458.txt">Table of n, a(n) for n = 1..111</a> %F A228458 Empirical: a(n) = 6*a(n-1) -15*a(n-2) +20*a(n-3) -14*a(n-5) +49*a(n-6) +8*a(n-7) +15*a(n-8) +54*a(n-9) +21*a(n-10) +20*a(n-11) +26*a(n-12) +10*a(n-13) +5*a(n-14) +4*a(n-15) +a(n-16). %e A228458 Some solutions for n=4 %e A228458 ..5....4....4....5....3....1....4....4....3....0....5....1....4....5....5....4 %e A228458 ..2....2....3....5....3....2....0....0....3....1....2....1....4....3....0....0 %e A228458 ..4....3....0....4....1....3....2....3....3....1....0....3....4....4....0....0 %e A228458 ..4....4....3....1....3....3....4....4....2....5....3....3....4....4....2....3 %Y A228458 Cf. A228461. %K A228458 nonn %O A228458 1,1 %A A228458 _R. H. Hardin_, Aug 22 2013