21355963domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = Sum_{k=0,1,2,...,n-4,n-2,n-1} a(k); a(n-3) is not a summand, with a(0)=0, a(1)=1, a(2)=3.at n=28A049859Prime numbersat n=1351036