A039965 An example of a d-perfect sequence.

1, 2, 2, 1, 2, 0, 0, 0, 2, 1, 2, 2, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 2, 2, 1, 2, 0, 0, 0, 2, 1, 2, 2, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 2, 2, 1, 2, 0, 0, 0, 2, 1, 2, 2, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,2

Links

Table of n, a(n) for n=1..105.

D. Kohel, S. Ling and C. Xing, Explicit Sequence Expansions, in Sequences and their Applications, C. Ding, T. Helleseth, and H. Niederreiter, eds., Proceedings of SETA'98 (Singapore, 1998), 308-317, 1999.

Formula

a(n) = ((-1)^(n+1)*A000108(n-1)) mod 3 - Christian G. Bower, Jun 12 2005

Prog

(PARI) C(n) = binomial(2*n, n)/(n+1);
a(n) = ((-1)^(n+1)*C(n-1)) % 3; \\ Michel Marcus, Jul 09 2016

Crossrefs

Cf. A000108.

Sequence in context: A016739 A158452 A208929 * A300481 A368509 A074942

Adjacent sequences: A039962 A039963 A039964 * A039966 A039967 A039968

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

More terms from Christian G. Bower, Jun 12 2005

Status

approved