cp's OEIS Frontend

A222550 Number of (n+3) X 1 arrays of occupancy after each element moves up to +-3 places but not 0.

%I A222550 #8 Aug 16 2018 08:58:40
%S A222550 31,102,359,1279,4537,15929,56041,197313,694561,2443809,8598567,
%T A222550 30254246,106446779,374510087,1317616614,4635657529,16309130459,
%U A222550 57378359687,201866467555,710197956209,2498584711494,8790394014302,30925899907467
%N A222550 Number of (n+3) X 1 arrays of occupancy after each element moves up to +-3 places but not 0.
%C A222550 Column 3 of A222555.
%H A222550 R. H. Hardin, <a href="/A222550/b222550.txt">Table of n, a(n) for n = 1..131</a>
%F A222550 Empirical: a(n) = 7*a(n-1) -15*a(n-2) +10*a(n-3) +4*a(n-4) -36*a(n-5) +73*a(n-6) -29*a(n-7) -21*a(n-8) -a(n-9).
%F A222550 Empirical g.f.: x*(31 - 115*x + 110*x^2 - 14*x^3 - 175*x^4 + 473*x^5 - 224*x^6 - 148*x^7 - 7*x^8) / (1 - 7*x + 15*x^2 - 10*x^3 - 4*x^4 + 36*x^5 - 73*x^6 + 29*x^7 + 21*x^8 + x^9). - _Colin Barker_, Aug 16 2018
%e A222550 Some solutions for n=3:
%e A222550 ..1....1....0....1....1....1....0....0....0....1....1....1....1....2....0....0
%e A222550 ..0....0....2....1....0....1....2....1....3....2....0....0....0....1....1....0
%e A222550 ..3....1....0....0....0....0....1....0....2....2....0....2....0....3....0....1
%e A222550 ..0....3....2....0....1....3....1....3....0....1....3....1....1....0....3....0
%e A222550 ..0....0....0....1....2....1....1....2....1....0....0....1....1....0....1....3
%e A222550 ..2....1....2....3....2....0....1....0....0....0....2....1....3....0....1....2
%Y A222550 Cf. A222555.
%K A222550 nonn
%O A222550 1,1
%A A222550 _R. H. Hardin_, Feb 24 2013