142382domain: NAppears in sequencesa(n) = Sum{a(k): k=0,1,2,...,n-3,n-1}; a(n-2) is not a summand; 2 initial terms required.at n=21A049855Number of (w,x,y,z) with all terms in {1,...,n} and w*x<=y*z+2.at n=23A212055Expansion of ( Sum_{k>=0} k^2 * q^(k^2) )^4.at n=52A347803