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A051638 a(n) = sum_{k=0..n} (C(n,k) mod 3). 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; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums of the triangle in A083093. - Reinhard Zumkeller, Jul 11 2013

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..6561=3^8

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, Ahmed Fares (ahmedfares(AT)my-deja.com) and others, Jul 16 2001

PROG

(Haskell)

a051638 = sum . a083093_row  -- Reinhard Zumkeller, Jul 11 2013

CROSSREFS

Cf. A001316.

Sequence in context: A286536 A166242 A143107 * A286580 A286598 A286557

Adjacent sequences:  A051635 A051636 A051637 * A051639 A051640 A051641

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified February 21 16:28 EST 2018. Contains 299414 sequences. (Running on oeis4.)