cp's OEIS Frontend

A166813 Number of n X 8 1..2 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in nondecreasing order.

%I A166813 #16 May 25 2016 22:04:28
%S A166813 7,43,163,493,1285,3001,6433,12868,24308,43756,75580,125968,203488,
%T A166813 319768,490312,735469,1081573,1562273,2220073,3108103,4292143,5852923,
%U A166813 7888723,10518298,13884154,18156202,23535818,30260338,38608018,48903490,61523746,76904683
%N A166813 Number of n X 8 1..2 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in nondecreasing order.
%H A166813 G. C. Greubel, <a href="/A166813/b166813.txt">Table of n, a(n) for n = 1..1000</a>
%F A166813 a(n) = A000581(n+8)-2. - _Alois P. Heinz_, May 31 2012
%F A166813 From _G. C. Greubel_, May 24 2016: (Start)
%F A166813 G.f.: 1/(1-x)^9 - (1+x)/(1-x).
%F A166813 E.g.f.: (1/8!)*(-40320 + 322560*x + 564480*x^2 + 376320*x^3 + 117600*x^4 + 18816*x^5 + 1568*x^6 + 64*x^7 + x^8)*exp(x) + 1. (End)
%e A166813 Some solutions for n=4
%e A166813 ...1.1.1.1.1.2.2.2...1.1.1.1.1.1.2.2...1.1.1.1.1.1.2.2...1.1.1.1.1.1.2.2
%e A166813 ...1.1.1.1.1.2.2.2...1.1.1.2.2.2.2.2...1.1.1.1.1.1.2.2...1.1.1.1.1.2.2.2
%e A166813 ...1.2.2.2.2.2.2.2...1.1.1.2.2.2.2.2...1.1.1.2.2.2.2.2...1.1.1.2.2.2.2.2
%e A166813 ...1.2.2.2.2.2.2.2...1.1.2.2.2.2.2.2...1.1.2.2.2.2.2.2...1.1.1.2.2.2.2.2
%e A166813 ------
%e A166813 ...1.1.1.1.1.1.1.1...1.1.1.1.1.1.1.2...1.1.1.1.1.1.1.2...1.1.1.1.1.1.2.2
%e A166813 ...1.1.1.1.1.1.1.1...1.1.1.1.1.1.1.2...1.1.1.1.1.2.2.2...1.2.2.2.2.2.2.2
%e A166813 ...1.2.2.2.2.2.2.2...1.1.1.1.1.1.1.2...1.1.1.2.2.2.2.2...2.2.2.2.2.2.2.2
%e A166813 ...1.2.2.2.2.2.2.2...1.2.2.2.2.2.2.2...1.1.2.2.2.2.2.2...2.2.2.2.2.2.2.2
%p A166813 a:= n-> binomial(n+8,8)-2:
%p A166813 seq (a(n), n=1..40);  # _Alois P. Heinz_, May 31 2012
%t A166813 Table[Binomial[n+8,8] -2, {n, 1, 100}] (* _G. C. Greubel_, May 24 2016 *)
%K A166813 nonn
%O A166813 1,1
%A A166813 _R. H. Hardin_, Oct 21 2009