198241domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes of the form x^2 + 17*y^2, where x and y=x+1 are consecutive natural numbers.at n=21A176622Number of 2 X 2 matrices having all terms in {-n,...,0,...,n} and nonnegative determinant.at n=12A211147Prime numbersat n=17840