21469

Appears in sequences

• Numbers k such that the number of prime divisors of the k-th Catalan number (counted with multiplicity) divides k.at n=36A121612
• Arithmetic mean of primes on square intervals such that the mean is an integer.at n=20A161348
• Triangle read by rows: coefficients of the polynomials given by KummerU(-n, 1 - n - x, 3).at n=31A327997
• a(0)=0; for n > 0, a(n) = a(n-1)*n + n if n is odd, (a(n-1) + n)*n otherwise.at n=7A344496
• a(n) = Sum_{k=1..n} sigma(n*k).at n=26A372710
• Expansion of e.g.f. -log(1 - x)^3 * exp(3*x) / 6.at n=7A382701