21570

Appears in sequences

• Fibonacci sequence beginning 3, 20.at n=16A022129
• a(n) = position of n^3 + (n+1)^3 + (n+2)^3 in A024975.at n=40A024980
• Terms in A112039 that are divisible by 3, divided by 3.at n=34A112040
• Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only either four adjacent vertically or four adjacent horizontally.at n=13A145791
• G.f. satisfies: A(x) = x + A( A(x)^2/(1 + A(x)^2) ).at n=10A213264
• Number of length 3+1 0..n arrays with the sum of the minimum of each adjacent pair multiplied by some arrangement of +-1 equal to zero.at n=20A250420
• Numbers whose binary indices have (1) prime indices covering an initial interval and (2) squarefree product.at n=43A371293