A171497 a(n) = 2*a(n-1) for n > 1; a(0) = 3, a(1) = 8.

3, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648, 4294967296, 8589934592, 17179869184

Offset

0,1

Comments

8*A000079 preceded by 3.

Binomial transform of A010703.

Inverse binomial transform of A171498.

Links

Table of n, a(n) for n=0..32.

Index entries for linear recurrences with constant coefficients, signature (2).

Formula

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

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

E.g.f.: 4*exp(2*x) - 1. - Stefano Spezia, Aug 04 2024

Mathematica

Join[{3}, NestList[2#&, 8, 30]] (* Harvey P. Dale, Dec 17 2011 *)

Prog

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

Crossrefs

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

Sequence in context: A001978 A173283 A077552 * A024623 A337118 A344509

Adjacent sequences: A171494 A171495 A171496 * A171498 A171499 A171500

Keyword

nonn,easy

Author

Klaus Brockhaus, Dec 10 2009

Extensions

a(30)-a(32) from Stefano Spezia, Aug 04 2024

Status

approved