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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
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
MATHEMATICA
Table[Sum[Mod[Binomial[2*i, i], 3], {i, 0, n}], {n, 0, 80}] (* Harvey P. Dale, Aug 08 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Nov 19, 2003
STATUS
approved