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

Author

Benoit Cloitre, Nov 19 2003

Keywords

• nonn

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

Crossrefs

Cf. A001285, A005836, A006996.

Programs

Mathematica

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