21749

Appears in sequences

• Number of partitions satisfying cn(2,5) + cn(3,5) < cn(1,5) + cn(4,5).at n=39A039893
• Numbers k such that the number of prime divisors of the k-th Catalan number (counted with multiplicity) divides k.at n=39A121612
• an=n-th smallest integer m=p1*p2*p3, product of 3 odd primes such that d+2m/d are all primes for d dividing 2m.at n=16A128278
• Products of three distinct happy primes A035497.at n=29A154717
• Indices of squares of primes in A098550.at n=36A251240
• Number of (n+2) X (3+2) 0..4 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=9A252956
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 579", based on the 5-celled von Neumann neighborhood.at n=28A273028
• a(n) = Sum_{k=1..n} sigma_2(k)^2.at n=8A356535