39997

Appears in sequences

• Numbers k such that the number of primes between k and 2k (inclusive) is equal to the number of primes between k and reverse(k) (inclusive).at n=33A074814
• Antidiagonal sums of square array A082025.at n=37A082190
• Numbers k such that 2k-1 is the digit reversal of k.at n=4A083818
• Number of nondecreasing Dyck paths of semilength n and having no peaks at even level (n>=0). A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.at n=16A121485
• Composite squarefree numbers that are multiples of the root mean square of their prime factors.at n=5A255356
• Positive integers that are square roots of products a*(a+d)*(a+2*d) with coprime a > 0, d >= 0.at n=13A284876