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A009984
Powers of 40.
3
1, 40, 1600, 64000, 2560000, 102400000, 4096000000, 163840000000, 6553600000000, 262144000000000, 10485760000000000, 419430400000000000, 16777216000000000000, 671088640000000000000, 26843545600000000000000
OFFSET
0,2
COMMENTS
Same as Pisot sequences E(1, 40), L(1, 40), P(1, 40), T(1, 40). Essentially same as Pisot sequences E(40, 1600), L(40, 1600), P(40, 1600), T(40, 1600). See A008776 for definitions of Pisot sequences.
The compositions of n in which each natural number is colored by one of p different colors are called p-colored compositions of n. For n >= 1, a(n) equals the number of 40-colored compositions of n such that no adjacent parts have the same color. - Milan Janjic, Nov 17 2011
FORMULA
G.f.: 1/(1 - 40*x). - Philippe Deléham, Nov 24 2008
a(n) = 40^n; a(n) = 40*a(n-1) a(0) = 1. - Vincenzo Librandi, Nov 21 2010
MATHEMATICA
40^Range[0, 19] (* Alonso del Arte, Sep 04 2016 *)
PROG
(Magma) [40^n: n in [0..20]] // Vincenzo Librandi, Nov 21 2010
(PARI) a(n)=40^n \\ Charles R Greathouse IV, Jun 19 2015
(PARI) powers(40, 10) \\ Charles R Greathouse IV, Jun 19 2015
CROSSREFS
Cf. A000302 (powers of 4), A011557 (powers of 10).
Sequence in context: A207425 A207740 A208082 * A041761 A229635 A278431
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Dec 11 1996
STATUS
approved