19827

Appears in sequences

• a(n+1) = a(n)-th composite and a(1) = 13.at n=36A059408
• Number of configurations of the sliding block 8-puzzle that require a minimum of n moves to be reached, starting with the empty square at mid-side.at n=22A089483
• Numbers k for which 5*k-4, 5*k-2, 5*k+2, and 5*k+4 are primes.at n=36A178082
• Number of n X n 0..4 arrays with rows and columns lexicographically nondecreasing and no element equal to the number of horizontal and vertical neighbors equal to itself.at n=2A201721
• Number of nX3 0..4 arrays with rows and columns lexicographically nondecreasing and no element equal to the number of horizontal and vertical neighbors equal to itself.at n=2A201724
• T(n,k)=Number of nXk 0..4 arrays with rows and columns lexicographically nondecreasing and no element equal to the number of horizontal and vertical neighbors equal to itself.at n=12A201729
• Number of (w,x,y,z) with all terms in {1,...,n} and w^2>=x^2+y^2+z^2.at n=20A212095
• a(n) is obtained by applying the map k -> composite(k) n times, starting at n.at n=33A280327
• Triangle T(n,k) read by rows: coefficients of polynomials P_n(t) defined in Formula section.at n=43A287030