113224domain: NAppears in sequencesNumbers k such that 5*10^k - 81 is prime.at n=27A281512a(n) is the permanent of the n X n matrix M(n) that is defined by M[i,j] = i*j - ceiling(i*j/3).at n=5A358163a(n) = Sum_{k=0..n} (-1)^k * binomial(4*k,n-k).at n=18A360088