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A113047 a(n) = C(3n,n)/(2n+1) mod 3. 4
1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 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, 0, 0, 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, 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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Conjecture: a(n) differs from 0 only when n=(3^j-1)/2,j=0,1,...

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..29524

FORMULA

G.f.: A(x) satisfies A(x)=1+x*A(x^3). - Vladimir Kruchinin, Mar 24 2015

a(n) = A001764(n) mod 3. - Michel Marcus, Mar 24 2015

MATHEMATICA

Table[Mod[Binomial[3 n, n]/(2 n + 1), 3], {n, 0, 72}] (* Michael De Vlieger, Mar 24 2015 *)

PROG

(PARI) A113047(n) = ((binomial(3*n, n)/(n+n+1))%3); \\ Antti Karttunen, Aug 28 2017

CROSSREFS

Cf. A001764, A003462, A010872, A039969.

Sequence in context: A015024 A016039 A138149 * A214505 A127692 A014305

Adjacent sequences:  A113044 A113045 A113046 * A113048 A113049 A113050

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Oct 11 2005

EXTENSIONS

More terms from Antti Karttunen, Aug 28 2017

STATUS

approved

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Last modified October 21 14:04 EDT 2019. Contains 328299 sequences. (Running on oeis4.)