18663

Appears in sequences

• Convolution of Catalan numbers and squares.at n=10A014316
• Numbers n such that 289*2^n-1 is prime.at n=18A050903
• n(k) is the minimum n that requires at least k to make 2*Prime[n]+Prime[k] a prime.at n=45A114234
• a(n) = 7*a(n-1) - 6*a(n-2), n>1; a(0)=1, a(1)=3.at n=6A152596
• a(n) = 10*n^2 + 4*n + 1.at n=43A272039
• a(n) = A273059(4n).at n=24A275916
• Numbers k such that (2*10^k - 179)/3 is prime.at n=15A295394
• Take a squarefree semiprime and take the difference of its prime factors. If it is a squarefree semiprime repeat the process. Sequence lists the squarefree semiprimes that generate other squarefree semiprimes only in the first k steps of this process. Case k = 4.at n=37A296811
• Take a squarefree semiprime and take the difference of its prime factors. If it is a squarefree semiprime repeat the process. Sequence lists the squarefree semiprimes that generate other squarefree semiprimes only in the first k steps of this process. Case k = 5.at n=10A296812
• Take a squarefree semiprime and take the difference of its prime factors. If it is a squarefree semiprime repeat the process. Sequence lists the squarefree semiprimes that generate other squarefree semiprimes only in the first k steps of this process. Case k = 6.at n=2A296813
• Number of separable partitions of n in which the number of distinct (repeatable) parts is > 2.at n=37A325717