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A051638 Sum_{k=0..n} (C(n,k) mod 3). +0
8
1, 2, 4, 2, 4, 8, 4, 8, 13, 2, 4, 8, 4, 8, 16, 8, 16, 26, 4, 8, 13, 8, 16, 26, 13, 26, 40, 2, 4, 8, 4, 8, 16, 8, 16, 26, 4, 8, 16, 8, 16, 32, 16, 32, 52, 8, 16, 26, 16, 32, 52, 26, 52, 80, 4, 8, 13, 8, 16, 26, 13, 26, 40, 8, 16, 26, 16, 32, 52, 26, 52, 80, 13 (list; graph; listen)
OFFSET

0,2

LINKS

Michael Gilleland, Some Self-Similar Integer Sequences

A. Granville, Binomials modulo a prime

FORMULA

Write n in base 3; if the representation contains r 1's and s 2's then a(n) = 2^{r-1} * (3^(s+1) - 1) = 1/2 * (3*A006047(n) - 2^(A062756(n))). - Robin Chapman (rjc(AT)MATHS.EX.AC.UK), Ahmed Fares (ahmedfares(AT)my-deja.com) and others, Jul 16, 2001

CROSSREFS

Cf. A001316.

Sequence in context: A128859 A047975 A112791 this_sequence A055372 A136620 A108445

Adjacent sequences: A051635 A051636 A051637 this_sequence A051639 A051640 A051641

KEYWORD

nonn

AUTHOR

njas

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Last modified July 8 18:40 EDT 2008. Contains 141013 sequences.


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