A088564 a(n)=sum(i=0,n,binomial(2*i,i) (mod 3)).

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

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