OFFSET
0
COMMENTS
Equals 1 if and only if the binary expansion of n does not contain two 1's in consecutive positions and ends in a 1.
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..65537
M. Elder and V. Vatter, Problems and Conjectures presented at the Third International Conference on Permutation Patterns, University of Florida, March 7-11, 2005, arXiv:math/0505504 [math.CO], 2005.
FORMULA
MATHEMATICA
Table[Mod[2/((n + 1) (2 n + 1)) Binomial[3 n, n], 2], {n, 0, 100}]
PROG
(PARI) a(n)=binomial(3*n, n)*2/((n+1)*(2*n+1)) % 2; \\ Michel Marcus, Apr 02 2019
(PARI) A324964(n) = ((n%2)&&!bitand(n, n<<1)); \\ Antti Karttunen, Aug 22 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Defant, Mar 21 2019
EXTENSIONS
Secondary name and more terms added by Antti Karttunen, Aug 22 2019
STATUS
approved