A084568 a(0)=1, a(1)=5, a(n+2)=4a(n), n>0.

1, 5, 8, 20, 32, 80, 128, 320, 512, 1280, 2048, 5120, 8192, 20480, 32768, 81920, 131072, 327680, 524288, 1310720, 2097152, 5242880, 8388608, 20971520, 33554432, 83886080, 134217728, 335544320, 536870912, 1342177280, 2147483648

Offset

0,2

Comments

Binomial transform is A080926 (without leading zero).

Links

Table of n, a(n) for n=0..30.

Index entries for linear recurrences with constant coefficients, signature (0,4)

Formula

G.f.: (1+5*x+4*x^2)/((1+2*x)*(1-2*x)).

E.g.f.: (9*exp(2*x)-exp(-2*x))/4-exp(0).

a(n) = (9*2^n-(-2)^n)/4-0^n.

Mathematica

Join[{1}, LinearRecurrence[{0, 4}, {5, 8}, 30]] (* Harvey P. Dale, Sep 12 2013 *)

Crossrefs

Cf. A080926, A104721.

Sequence in context: A271195 A270630 A272217 * A340509 A198635 A178675

Adjacent sequences: A084565 A084566 A084567 * A084569 A084570 A084571

Keyword

nonn,easy

Author

Paul Barry, May 30 2003

Status

approved