A171497 - OEIS

%I #23 Aug 04 2024 22:05:14

%S 3,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,

%T 131072,262144,524288,1048576,2097152,4194304,8388608,16777216,

%U 33554432,67108864,134217728,268435456,536870912,1073741824,2147483648,4294967296,8589934592,17179869184

%N a(n) = 2*a(n-1) for n > 1; a(0) = 3, a(1) = 8.

%C 8*A000079 preceded by 3.

%C Binomial transform of A010703.

%C Inverse binomial transform of A171498.

%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (2).

%F a(n) = 4*2^n for n > 0; a(0) = 3.

%F G.f.: (3+2*x)/(1-2*x).

%F E.g.f.: 4*exp(2*x) - 1. - _Stefano Spezia_, Aug 04 2024

%t Join[{3},NestList[2#&,8,30]] (* _Harvey P. Dale_, Dec 17 2011 *)

%o (PARI) {m=30; v=concat([3, 8], vector(m-2)); for(n=3, m, v[n]=2*v[n-1]); v}

%Y Cf. A000079 (powers of 2), A010703 (repeat 3, 5), A171498.

%K nonn,easy

%O 0,1

%A _Klaus Brockhaus_, Dec 10 2009

%E a(30)-a(32) from _Stefano Spezia_, Aug 04 2024