604049domain: NAppears in sequencesa(n) = a(1) + a(2) + ... + a(n-1) + a(m), where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n-1 <= 2^(p+1), starting with a(1) = a(2) = 1.at n=19A049941Expansion of (1 + x^2 - x^3)/((1 + x^2 - x^3)^2 - 4*x^2).at n=25A376726Expansion of 1 / ((1-x)^4 - x^6).at n=22A392542