806609domain: NPropertiesPrimalityPrimeyesAppears in sequencesEvery digit of prime and its index contains a loop (only digits 0,4,6,8,9 in prime and its index).at n=20A107625Number of nX5 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,3,0,1,4 for x=0,1,2,3,4.at n=7A196490Prime numbersat n=64444