19698

Appears in sequences

• Number of 4-block ordered bicoverings of an unlabeled n-set.at n=16A060091
• Numbers k such that sigma(sigma(k)) == phi(k) (mod sigma(k)).at n=14A067204
• Numbers n such that for some m, A166133(m)=n, A166133(m+1)=n^2-1, in order of increasing m.at n=29A256406
• Numbers n such that for some m, A166133(m)=n, A166133(m+1)=n^2-1, in increasing order.at n=32A256407
• Numbers k such that k is the average of four consecutive primes k-11, k-1, k+1 and k+11.at n=20A259025
• Numbers n such that n^2048 + (n+1)^2048 is prime.at n=19A274235
• Expansion of Product_{k>0} (1 - q^(3*k))^5/((1 - q^k)^3*(1 - q^(6*k))^2).at n=18A293423
• Triangle read by rows: T(n,k) = number of noncrossing path sets on n nodes up to rotation with k paths and isolated vertices allowed.at n=60A303869
• Ulam numbers sandwiched between twin prime numbers.at n=33A380429