24198

Appears in sequences

• a(0) = 1, a(1) = 0, a(n+1) = 2*a(n) + (2*n-1)^2*a(n-1).at n=7A024200
• Denominators of continued fraction convergents to sqrt(756).at n=5A042457
• a(n)=phi(n^2+1)/n if (n^2+1) is composite and phi(n^2+1)==0 (mod n).at n=35A067926
• 6 times octagonal numbers: a(n) = 6*n*(3*n-2).at n=37A153796
• The even composites c such that c=q*g*j*y and q+g=j*y where q,g,j,y are primes.at n=37A167690
• Number of weakly ordered plane trees with n leaves.at n=11A196545
• Nonnegative integers n such that in balanced ternary representation the number of occurrences of each trit doubles when n is squared.at n=31A257867
• Least positive integer m with prime(m)+2 and prime(prime(m))+2 both prime such that prime(m*n)+2 and prime(prime(m*n))+2 are both prime.at n=27A259487
• Number of complete tree-partitions of a multiset whose multiplicities are the prime indices of n.at n=36A318848
• Numbers k such that phi(k) and phi(k+1) are perfect powers (A001597).at n=42A332008