55127domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes that remain prime through 4 iterations of function f(x) = 4x + 3.at n=22A023311Primes of the form 5*k^2 + 2, k >= 0.at n=18A201481Primes equal to a centered heptagonal number plus 1.at n=20A285811Number of closable Motzkin trees.at n=14A300125Prime numbersat n=5603