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 A189583 #7 Jun 02 2025 04:02:23 %S A189583 1,1,2,4,13,26,62,132,274,614,1315,2955,6423,14058,30838,67170,147553, %T A189583 322304,706400,1546128,3382752,7408261,16208271,35489093,77672999, %U A189583 170021833,372181083,814611385,1783211187,3903138418,8543748906 %N A189583 Number of permutations of 1..n with displacements restricted to {-4,-2,0,1,3}. %H A189583 R. H. Hardin, <a href="/A189583/b189583.txt">Table of n, a(n) for n = 1..200</a> %F A189583 Empirical: a(n) = a(n-1) +2*a(n-3) +3*a(n-4) +7*a(n-5) +25*a(n-7) -10*a(n-8) +7*a(n-9) -5*a(n-10) -23*a(n-11) -15*a(n-12) -4*a(n-13) -66*a(n-14) +23*a(n-15) -5*a(n-16) +16*a(n-17) +28*a(n-18) -14*a(n-19) +4*a(n-20) +55*a(n-21) -13*a(n-22) -7*a(n-23) -16*a(n-24) -8*a(n-25) +14*a(n-26) -2*a(n-27) -15*a(n-28) +a(n-30) +3*a(n-31) +a(n-32) -a(n-33) +a(n-35) %e A189583 Some solutions for n=10 %e A189583 ..1....3....3....1....1....1....1....1....5....1....3....5....1....1....1....5 %e A189583 ..4....1....1....4....2....2....2....6....2....2....2....1....2....2....6....2 %e A189583 ..2....2....2....2....5....3....3....7....3....7....7....2....5....3....3....3 %e A189583 ..8....4....4....3....6....8....6....3....1....4....1....6....3....4....4....1 %e A189583 ..5....9....5....5....9....4....4....2....9....5....9....9....7....5....2....4 %e A189583 ..3....5....8....8....3....5....5....5....8....3....8....3....8....6....5....6 %e A189583 ..9....6....7....9....4....6....9....4....4....6....4....4....4....7....9....9 %e A189583 ..7...10...10....7....7....7...10...10...10....8....5....7...10...10...10...10 %e A189583 ..6....8....6....6....8....9....8....8....6....9....6....8....6....8....8....8 %e A189583 .10....7....9...10...10...10....7....9....7...10...10...10....9....9....7....7 %K A189583 nonn %O A189583 1,3 %A A189583 _R. H. Hardin_ Apr 24 2011