21255

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 15 ones.at n=27A031783
• a(n) = n*(14*n - 1).at n=39A195024
• Numbers k at which point A336459(k) appears multiplicative, but A051027(k) does not.at n=38A336561
• Numbers k such that A353802(k) / sigma(sigma(k)) is an integer > 1, where A353802(n) = Product_{p^e||n} sigma(sigma(p^e)).at n=12A353807
• Antidiagonal sums of the array A380841.at n=7A380843