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A039971 An example of a d-perfect sequence. 1
1, 1, 2, 0, 0, 1, 2, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 2, 1, 0, 0, 2, 1, 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, 1, 2, 2, 1, 0, 0, 2, 1, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 2, 0, 0, 1, 2, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

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. DOI: 10.1007/978-1-4471-0551-0_23

FORMULA

a(n) = ((-1)^(n+1)*A007317(n)) mod 3 - Christian G. Bower, Jun 12 2005

a(n) = A001405(n-1) mod 3. - John M. Campbell, Jul 19 2016

MATHEMATICA

Table[Mod[Binomial[n - 1, Floor[(n - 1)/2]], 3], {n, 120}] (* or *)

Table[Function[n, Mod[-(-1)^(n + 1) Sum[Binomial[n, k] CatalanNumber@ k, {k, 0, n}], 3]][n - 1], {n, 120}] (* Michael De Vlieger, Jul 19 2016 *)

PROG

(MAGMA) [Binomial(n, Floor(n/2)) mod 3: n in [0..140]]; // Vincenzo Librandi, Jul 20 2016

CROSSREFS

Sequence in context: A303065 A325406 A257900 * A205593 A277937 A334913

Adjacent sequences:  A039968 A039969 A039970 * A039972 A039973 A039974

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Christian G. Bower, Jun 12 2005

STATUS

approved

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Last modified January 24 21:08 EST 2022. Contains 350565 sequences. (Running on oeis4.)