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A084568 a(0)=1, a(1)=5, a(n+2)=4a(n), n>0. 1
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 (list; graph; refs; listen; history; text; internal format)
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. A104721.

Sequence in context: A271195 A270630 A272217 * A198635 A178675 A271087

Adjacent sequences:  A084565 A084566 A084567 * A084569 A084570 A084571

KEYWORD

nonn,easy

AUTHOR

Paul Barry, May 30 2003

STATUS

approved

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Last modified July 5 04:19 EDT 2020. Contains 335459 sequences. (Running on oeis4.)