193601

Properties

Appears in sequences

• Fibonacci sequence beginning 1, 28.at n=20A022398
• Numbers k such that 21^k - 20^k is prime.at n=12A062587
• a(n) is the n-th prime of the form n*x^2+1.at n=24A128970
• Lower twin primes p1 such that p1-1 is a square.at n=17A145824
• Primes of the form p^2 + 2*p + 2 where p is prime.at n=22A157467
• Primes p of form n^2 + 1 such that p+2 and p+6 are also prime.at n=6A200992
• Primes p such that p plus the cube of sum of digits of p is a perfect square.at n=31A259418
• Primes p such that gcd(phi(p-1), sigma(p-1)) = 1 with phi = A000010, sigma = A000203.at n=38A270539
• Primes p of the form k^2 + 1 such that p+2 and 2p+1 are also prime.at n=2A347934
• Smallest prime p == 1 (mod 8) such that Q(sqrt(p)) has class number 2n+1.at n=30A355876
• Smallest p == 1 (mod 4) such that Q(sqrt(p)) has class number 2n+1.at n=30A355878
• Prime numbersat n=17464