A278671 - OEIS

%I #8 Feb 10 2019 07:00:34

%S 4,33,158,579,1801,4999,12727,30218,67651,143936,292799,572247,

%T 1078870,1968906,3488570,6016844,10124758,16656179,26836284,42415243,

%U 65856199,100578425,151268585,224275350,328105245,474040554,676903413,955993903

%N Number of n X 3 0..1 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly one mistake.

%H R. H. Hardin, <a href="/A278671/b278671.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (1/39916800)*n^11 + (1/907200)*n^10 + (17/725760)*n^9 + (19/60480)*n^8 + (3691/1209600)*n^7 + (1003/43200)*n^6 + (21115/145152)*n^5 + (106243/181440)*n^4 + (1170209/907200)*n^3 + (35051/25200)*n^2 + (7783/13860)*n.

%F Empirical g.f.: x*(4 - 15*x + 26*x^2 - 19*x^3 + x^4 + 8*x^5 - 5*x^6 + x^7) / (1 - x)^12. - _Colin Barker_, Feb 10 2019

%e Some solutions for n=4:

%e ..0..0..0. .1..1..0. .1..1..0. .1..1..0. .1..0..0. .1..1..1. .1..0..0

%e ..1..1..1. .1..1..0. .1..1..1. .0..0..0. .1..1..0. .1..1..1. .1..1..0

%e ..0..0..0. .0..0..1. .1..0..1. .1..0..1. .0..1..1. .1..1..1. .0..1..0

%e ..1..1..1. .1..0..1. .1..0..1. .1..1..1. .1..0..1. .1..1..0. .0..1..0

%Y Column 3 of A278676.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 25 2016