Search: id:A007009 Results 1-1 of 1 results found. %I A007009 M3435 %S A007009 1,4,12,27,54,96,160,250,375,540,756,1029,1372,1792,2304,2916,3645, %T A007009 4500,5500,6655,7986,9504,11232,13182,15379,17836,20580,23625,27000, %U A007009 30720,34816,39304,44217,49572,55404,61731,68590,76000,84000,92610 %N A007009 Number of 3-voter voting schemes with n linearly ranked choices. %D A007009 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A007009 D. E. Loeb (daniel.loeb(AT)verizon.net), On Games, Voting Schemes and Distributive Lattices. LaBRI Report 625-93, University of Bordeaux I, 1993. %F A007009 G.f.: (1 - x^3 ) / (1 - x)^4 (1 - x^2 )^2. %F A007009 a(n) = (1/2)*Sum_{k=1..n+1} k*floor(k/2)*ceil(k/2). - Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 29 2006 %F A007009 G.f.: x (1 - x^3 ) / ((1 - x)^4 (1 - x^2 )^2). [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Aug 13 2008] %p A007009 a := n-> (Matrix([[0$4,1,4,12,27]]). Matrix(8, (i,j)-> if (i=j-1) then 1 elif j=1 then [4,-4,-4,10,-4,-4,4,-1][i] else 0 fi)^n)[1,1]; seq (a(n), n=1..40); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Aug 13 2008] %Y A007009 A006009/4. %Y A007009 Sequence in context: A047732 A104385 A062479 this_sequence A104384 A013697 A064444 %Y A007009 Adjacent sequences: A007006 A007007 A007008 this_sequence A007010 A007011 A007012 %K A007009 nonn %O A007009 1,2 %A A007009 Daniel LOEB, daniel.loeb(AT)verizon.net %E A007009 More terms from James A. Sellers (sellersj(AT)math.psu.edu), Sep 08 2000 Search completed in 0.001 seconds