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A009984 Powers of 40. 2
1, 40, 1600, 64000, 2560000, 102400000, 4096000000, 163840000000, 6553600000000, 262144000000000, 10485760000000000, 419430400000000000, 16777216000000000000, 671088640000000000000, 26843545600000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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

LINKS

T. D. Noe, Table of n, a(n) for n=0..100

Tanya Khovanova, Recursive Sequences

FORMULA

G.f.: 1/(1-40*x). [From Philippe Deléham, Nov 24 2008]

a(n)=40^n; a(n)=40*a(n-1) a(0)=1 [From Vincenzo Librandi, Nov 21 2010]

PROG

(MAGMA)[40^n: n in [0..20]] [From Vincenzo Librandi, Nov 21 2010]

CROSSREFS

Sequence in context: A207425 A207740 A208082 * A041761 A229635 A229584

Adjacent sequences:  A009981 A009982 A009983 * A009985 A009986 A009987

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified October 1 18:25 EDT 2014. Contains 247522 sequences.