224085domain: NAppears in sequencesDefine two sequences by A_n = mex{A_i,B_i : 0 <= i < n} for n >= 0, B_0=0, B_1=1 and for n >= 2, B_n = 2B_{n-1}+(-1)^{A_n}. Sequence gives B_n.at n=18A080241Numbers k such that 381*2^k+1 is prime.at n=42A323033