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A013725
a(n) = 20^(2*n + 1).
3
20, 8000, 3200000, 1280000000, 512000000000, 204800000000000, 81920000000000000, 32768000000000000000, 13107200000000000000000, 5242880000000000000000000, 2097152000000000000000000000
OFFSET
0,1
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).
Sequence in context: A223051 A222744 A234459 * A307914 A293286 A250021
KEYWORD
nonn,easy
STATUS
approved