345241domain: NAppears in sequencesa(n) = a(n-1) + floor(a(n-2)/2) with a(0)=1, a(1)=2.at n=41A064324Number of -5..5 arrays of n elements with first, second and third differences also in -5..5.at n=6A202121Number of -n..n arrays of 7 elements with first, second and third differences also in -n..n.at n=4A202128