A103422 - OEIS

%I #8 Mar 29 2015 14:10:32

%S 0,1,2,5,9,18,34,66,127,249,490,972,1936,3874,7772,15623,31439,63308,

%T 127506,256782,516970,1040340,2092450,4206146,8449953,16965459,

%U 34042784,68272206,136847328,274168858,549042730,1099050180,2199222960

%N Number of compositions of n in which the greatest part is even.

%F G.f.: Sum((1-x)^2*x^(2*n)/((1-2*x+x^(2*n))*(1-2*x+x^(2*n+1))), n=1..infinity).

%t Rest[ CoefficientList[ Series[ Expand[ Sum[(1 - x)^2*x^(2n)/((1 - 2x + x^(2n))*(1 - 2x + x^(2n + 1))), {n, 35}]], {x, 0, 35}], x]] (* _Robert G. Wilson v_, Feb 05 2005 *)

%Y Cf. A103419, A103420, A103421, A027187, A027193, A026804, A026805.

%K easy,nonn

%O 1,3

%A _Vladeta Jovovic_, Feb 04 2005

%E More terms from _Robert G. Wilson v_, Feb 05 2005