38117

Appears in sequences

• Composite numbers which contain their largest proper divisor as a substring.at n=6A062238
• Triangle T(n, k, m) = (m*(n-k) + 1)*T(n-1, k-1, m) + (m*k + 1)*T(n-1, k, m) + m*f(n,k)*T(n-2, k-1, m) with T(n, 0, m) = T(n, n, m) = 1, f(n, k) = 2*k if k <= floor(n/2) otherwise 2*(n-k), and m = 1, read by rows.at n=31A157275
• Triangle T(n, k, m) = (m*(n-k) + 1)*T(n-1, k-1, m) + (m*k + 1)*T(n-1, k, m) + m*f(n,k)*T(n-2, k-1, m) with T(n, 0, m) = T(n, n, m) = 1, f(n, k) = 2*k if k <= floor(n/2) otherwise 2*(n-k), and m = 1, read by rows.at n=32A157275
• Smallest k such that 2^(2^n) - k is a safe prime.at n=7A181356
• Numbers n such that n'' = n'+1 where n' and n'' are respectively the first and the second arithmetic derivative of n (A003415).at n=10A189639
• Semiprimes generated by the polynomial 2 * n^2 + 29.at n=38A241554
• Number of compositions (ordered partitions) of n into centered pentagonal numbers (A005891).at n=44A322801
• Numbers k for which sigma(k) = k + k'', where k'' is the second derivative of k (A068346).at n=11A348426
• Composite numbers of the form 2*k^2 + 29.at n=38A352949