102672domain: NAppears in sequencesNumbers k such that 2k-1 divides 2^k-1.at n=38A081856Expansion of (1+x)^2/((1-2x)(1-3x)).at n=9A085277Primitive elements of A096490.at n=32A118671a(n) = Sum_{k=0..floor(n/3)} (k+1) * binomial(2*k,2*n-6*k).at n=29A382496