49813

Appears in sequences

• Numbers n such that sigma(reverse(n)) = phi(n).at n=19A070856
• Numbers k such that 2^k-61 is prime.at n=42A182156
• Semiprimes of the form p*q where p < q such that q divides p^(q+1) + 1 and (q-p)^(q+1) + 1.at n=15A278921
• Positive integers with binary expansion (b(1), ..., b(m)) such that Sum_{i = 1..m-k} b(i)*b(i+k) is odd for all k = 0..m-1.at n=9A360388
• E.g.f. satisfies A(x) = exp(x * (1 + x) * A(x^2)).at n=7A367747