190913domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = Sum_{k=0..n} (k+1) * A026747(n, n-k).at n=13A027228Number of n X 4 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.at n=13A281465Prime numbersat n=17242