3072365domain: NAppears in sequencesa(n) = C(n-2,2)+C(n-5,5)+...+C(n-(3*floor((n-3)/3)+2),3*floor((n-3)/3)+2).at n=34A101551a(n) = Sum_{k=0..floor(n/3)} binomial(n+3*k,n-3*k).at n=17A373905Expansion of (1 + x)^2/(1 - x^3*(1 + x)^3).at n=32A375321