3447071domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = ((n+2)/2)*Sum_{k=0..n/2} (Sum_{i=0..n-2*k} (binomial(k+1,n-2*k-i)*binomial(k+i,k))*F(k+1)/(k+1)), where F(k) is Fibonacci numbers.at n=20A270737Prime numbersat n=246711