209953

Properties

Appears in sequences

• Class 1- (or Pierpont) primes: primes of the form 2^t*3^u + 1.at n=34A005109
• Primes of form 1+(2^a)*(3^b), a>0, b>0.at n=28A058383
• Primes obtained as the product of successive terms of A084039 + 1, i.e., a(n) = A084039(n)*A084039(n+1) + 1.at n=19A084040
• Primes of the form 8*k^2 + 1.at n=19A090685
• Numbers n such that sigma(n) = 2n - 3*phi(phi(n)).at n=29A110074
• Greatest prime factor of 2*n^4 + 1.at n=17A140538
• Primes which are divisors of numbers of the form (2^phi(3^k) - 1)/3^k.at n=16A152008
• Primes of the form 2^i * 3^j + 1 with i + j = 13.at n=3A172488
• Generalized cuban primes (A007645) which are also Class 1- (or Pierpont) primes (A005109).at n=29A217035
• Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010001 00010101 or 01010101.at n=17A261106
• Numbers k such that 2^(3^j) == 1 (mod k) for some j.at n=14A318688
• Prime numbersat n=18802