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A088564 a(n)=sum(i=0,n,binomial(2*i,i) (mod 3)). 1
1, 3, 3, 5, 6, 6, 6, 6, 6, 8, 9, 9, 10, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 14, 15, 15, 16, 18, 18, 18, 18, 18, 19, 21, 21, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Distinct values (i.e. 1,3,5,6,8,9,...) are given by the partial sums of the Thue-Morse sequence on alphabet (1,2) A026430. Sequence of least k such that a(k)>a(k-1) is given by A005836. For any k>=0, card{ n : a(3*A005836(k)) =a(n)}=1.

Only 79 of the first 1001 terms are odd numbers.  -- From Harvey P. Dale, Aug 08 2012

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

MATHEMATICA

Table[Sum[Mod[Binomial[2*i, i], 3], {i, 0, n}], {n, 0, 80}] (* Harvey P. Dale, Aug 08 2012 *)

CROSSREFS

Cf. A001285, A005836, A006996.

Sequence in context: A204250 A131948 A134636 * A161560 A078796 A201929

Adjacent sequences:  A088561 A088562 A088563 * A088565 A088566 A088567

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Nov 19, 2003

STATUS

approved

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Last modified June 22 16:35 EDT 2021. Contains 345388 sequences. (Running on oeis4.)