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Number of compositions of n where the difference between largest and smallest parts equals 9 and adjacent parts are unequal.
2

%I #9 Jan 03 2019 15:14:54

%S 0,2,1,8,12,23,56,100,196,380,734,1360,2583,4831,8933,16629,30627,

%T 56359,103401,189241,345386,629284,1144379,2076985,3764633,6812624,

%U 12312124,22223544,40067505,72159773,129826552,233358096,419077220,751979608,1348268372

%N Number of compositions of n where the difference between largest and smallest parts equals 9 and adjacent parts are unequal.

%H Alois P. Heinz, <a href="/A214278/b214278.txt">Table of n, a(n) for n = 10..2000</a>

%e a(11) = 2: [10,1], [1,10].

%e a(12) = 1: [1,10,1].

%e a(13) = 8: [2,11], [2,10,1], [2,1,10], [11,2], [10,2,1], [10,1,2], [1,2,10], [1,10,2].

%e a(14) = 12: [3,10,1], [3,1,10], [2,1,10,1], [10,3,1], [10,1,3], [10,1,2,1], [1,3,10], [1,2,10,1], [1,2,1,10], [1,10,3], [1,10,2,1], [1,10,1,2].

%Y Column k=9 of A214269.

%K nonn

%O 10,2

%A _Alois P. Heinz_, Jul 09 2012