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A013725 a(n) = 20^(2*n + 1). 3
20, 8000, 3200000, 1280000000, 512000000000, 204800000000000, 81920000000000000, 32768000000000000000, 13107200000000000000000, 5242880000000000000000000, 2097152000000000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (400).

FORMULA

From Philippe Deléham, Nov 28 2008: (Start)

a(n) = 400*a(n-1); a(0)=20.

G.f.: 20/(1-400*x). (End)

MAPLE

seq(20^(2*n+1), n=0..10); # Nathaniel Johnston, Jun 25 2011

PROG

(MAGMA) [20^(2*n+1): n in [0..15]]; // Vincenzo Librandi, Jun 26 2011

(PARI) a(n)=20^(2*n+1) \\ Charles R Greathouse IV, Jul 11 2016

CROSSREFS

Bisection of A009964 (20^n).

Cf. A004171, A013708-A013724, A013726-A013729.

Sequence in context: A223051 A222744 A234459 * A293286 A250021 A203308

Adjacent sequences:  A013722 A013723 A013724 * A013726 A013727 A013728

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified November 19 19:28 EST 2018. Contains 317364 sequences. (Running on oeis4.)