69697

Properties

Appears in sequences

• Palindromic primes in base 3.at n=30A029971
• Primes p such that (p-1) and the period length of 1/p are both squares.at n=26A076516
• a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) + a(n-4).at n=13A093406
• a(n) = index of first appearance of n in A096862.at n=19A097008
• a(n) = Sum_{k=0..n} C(n,4k)*2^k.at n=16A097081
• Primes of the form a^5 + b^3 with a,b>0.at n=38A100273
• Primes with digit sum = 37.at n=19A106771
• Primes of the form 9*n^2 + 1.at n=15A156226
• Primes of the form p^2 + 2*p + 2 where p is prime.at n=15A157467
• a(n) = 64*n^2 + 1.at n=33A158686
• The smallest prime p such that tau(p-1) + tau(p+1) = prime(n), or 0 if no such prime exists; where tau(k) is the number of divisors of k.at n=18A189536
• Primes that can be written as a sum of a positive square and a positive cube in more than two ways.at n=10A206606
• Primes formed by concatenating k, k, and 7.at n=20A210513
• Numbers k such that distances from k to three nearest squares are three triangular numbers.at n=30A232501
• Primes whose base-8 representation also is the base-3 representation of a prime.at n=16A235471
• Primes having only {6, 7, 9} as digits.at n=32A261184
• Primes p such that gcd(phi(p-1), sigma(p-1)) = 1 with phi = A000010, sigma = A000203.at n=30A270539
• Löschian numbers (A003136) of the form k^2+1.at n=22A271184
• Square array read by antidiagonals downwards: for n >= 2, T(k,n) is the number of permutations of [k+n] that differ in every position from both the identity permutation and a permutation consisting of k 1-cycles and one n-cycle.at n=49A335391
• Smallest prime p == 1 (mod 8) such that Q(sqrt(p)) has class number 2n+1.at n=25A355876