A174316 - OEIS

%I #5 Feb 29 2016 14:19:04

%S 1,1,1,2,6,10,18,34,66,130,258,514,1026,2050,4098,8194,16386,32770,

%T 65538,131074,262146,524290,1048578,2097154,4194306,8388610,16777218,

%U 33554434,67108866,134217730,268435458,536870914,1073741826,2147483650

%N Sequence defined by a(0)=a(1)=a(2)=1, a(3)=2, a(4)=6 and the formula a(n)=2^(n-2)+2 for n>=5.

%F G.f f: f(z)=(1+z+z^2+2*z^3+6*z^4+((2*z^5)/(1-z))+((2*z)^5/(4*(1-2*z))))

%F a(n) = A052548(n-2), n>3 . - _R. J. Mathar_, Feb 29 2016

%e a(5)=2^3+2=10. a(6)=2^4+2=18.

%p taylor(((1+z^3+4*z^4-4*z^5)/(1-z))+((8*z^5)/(1-2*z)),z=0,50); v(0):=1:v(1):=1:v(2):=1:v(3):=2:v(4):=6: for n from 5 to 50 do v(n):=2^(n-2)+2:od:seq(v(n),n=0..50);

%Y Cf. A174314.

%K nonn,easy

%O 0,4

%A _Richard Choulet_, Mar 15 2010