75269

Properties

Appears in sequences

• Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k blocks of length 2 (0 <= k <= floor(n/2)). A block of a permutation is a maximal sequence of consecutive integers which appear in consecutive positions. For example, the permutation 5412367 has 4 blocks: 5, 4, 123, and 67; one of them is of length 2.at n=33A184183
• Primes of the form 6n^2 + 5.at n=35A201600
• Number of zero-sum nX1 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor.at n=20A201840
• Primes of the form 8n^2 - 3.at n=20A201856
• Primes p with pi(p), pi(pi(p)) and pi(p^2) all prime, where pi(.) is given by A000720.at n=14A237687
• a(n) = prime(k-1) with k = n^2 + prime(n)^2.at n=22A243893
• Primes p such that if q and r are the next two primes, 6*q-r, 6*q-p, 6*q+p and 6*q+r are all prime.at n=24A351636
• Prime numbersat n=7417