Search: id:A006980 Results 1-1 of 1 results found. %I A006980 M1411 %S A006980 1,2,5,12,28,64,143,315,687,1485,3186,6792,14401,30391,63872,133751, %T A006980 279177,581040,1206151,2497895,5161982,10646564,21919161,45052841, %U A006980 92461171,189489255,387830160,792810956,1618840800,3301999647 %N A006980 Compositions: 6th column of A048004. %D A006980 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A006980 J. L. Yucas, Counting special sets of binary Lyndon words, Ars Combin., 31 (1991), 21-29. %F A006980 G.f.: x^6 / ((1-x-x^2-x^3-x^4-x^5) * (1-x-x^2-x^3-x^4-x^5-x^6)). [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 29 2008] %p A006980 a:= n-> (Matrix(11, (i,j)-> if i=j-1 then 1 elif j=1 then [2, 1, 0, -1, -2, -4, -5, -4, -3, -2, -1][i] else 0 fi)^n) [1,7]: seq (a(n), n=6..40); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 29 2008] %Y A006980 Sequence in context: A111586 A006979 A019301 this_sequence A045623 A001410 A019486 %Y A006980 Adjacent sequences: A006977 A006978 A006979 this_sequence A006981 A006982 A006983 %K A006980 nonn %O A006980 6,2 %A A006980 Simon Plouffe (simon.plouffe(AT)gmail.com) %E A006980 More terms and better definition from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Oct 29 2008 %E A006980 Corrected definition: 6th column of A048004. - Geoffrey Critzer (critzer.geoffrey(AT)usd443.org), Nov 09 2008 Search completed in 0.010 seconds