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A051638
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a(n) = sum_{k=0..n} (C(n,k) mod 3).
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8
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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
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history;
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OFFSET
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0,2
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COMMENTS
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Row sums of the triangle in A083093. - Reinhard Zumkeller, Jul 11 2013
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LINKS
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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
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FORMULA
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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
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MATHEMATICA
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Table[2^(DigitCount[n, 3, 1]-1) (3^(DigitCount[n, 3, 2]+1)-1), {n, 0, 80}] (* Harvey P. Dale, Jun 20 2019 *)
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PROG
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(Haskell)
a051638 = sum . a083093_row -- Reinhard Zumkeller, Jul 11 2013
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CROSSREFS
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Cf. A001316.
Sequence in context: A318768 A166242 A143107 * A286580 A286598 A286557
Adjacent sequences: A051635 A051636 A051637 * A051639 A051640 A051641
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane
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STATUS
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approved
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