

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
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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 SelfSimilar 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^{r1} * (3^(s+1)  1) = 1/2 * (3*A006047(n)  2^(A062756(n))).  Robin Chapman, Ahmed Fares (ahmedfares(AT)mydeja.com) and others, Jul 16 2001


MATHEMATICA

Table[2^(DigitCount[n, 3, 1]1) (3^(DigitCount[n, 3, 2]+1)1), {n, 0, 80}] (* Harvey P. Dale, Jun 20 2019 *)


PROG

(Haskell)
a051638 = sum . a083093_row  Reinhard Zumkeller, Jul 11 2013


CROSSREFS

Cf. A001316.
Sequence in context: A318768 A166242 A143107 * A286580 A286598 A286557
Adjacent sequences: A051635 A051636 A051637 * A051639 A051640 A051641


KEYWORD

nonn


AUTHOR

N. J. A. Sloane


STATUS

approved



