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1, 27, 729, 19683, 531441, 14348907, 387420489, 10460353203, 282429536481, 7625597484987, 205891132094649, 5559060566555523, 150094635296999121, 4052555153018976267, 109418989131512359209, 2954312706550833698643
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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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 27-colored compositions of n such that no adjacent parts have the same color. - Milan Janjic, Nov 17 2011
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LINKS
| T. D. Noe, Table of n, a(n) for n=0..100
Tanya Khovanova, Recursive Sequences
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FORMULA
| G.f.: 1/(1-27*x). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 24 2008]
a(n)=27^n; a(n)=27*a(n-1) n>0 a(0)=1 [From Vincenzo Librandi, Nov 21 2010]
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PROG
| sage: from sage.combinat.sloane_functions import recur_gen2b sage: it =recur_gen2b(1, n/2, n/2, 0, lambda n: 0) sage: [it.next() for i in range(18)] - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 16 2008
(Other) sage: [lucas_number1(n, 27, 0) for n in xrange(1, 17)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 29 2009]
(MAGMA)[27^n: n in [0..100]] [From Vincenzo Librandi, Nov 21 2010]
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CROSSREFS
| Sequence in context: A167726 A171301 A098838 * A046240 A042406 A159668
Adjacent sequences: A009968 A009969 A009970 * A009972 A009973 A009974
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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