68111

Properties

Appears in sequences

• Expansion of (1+4*x)/(1-6*x+x^2).at n=6A054489
• Primes of the form p*q + p + q, where p and q are two successive primes.at n=24A096342
• Start with 1 and repeatedly reverse the digits and add 55 to get the next term.at n=25A118161
• a(n) = Sum_[k unrelated to n and k<n] a(k) = Sum_[k < n such that GCD(k,n) != 1 and k does not divide n ] a(k); a(1) = a(2) = a(3) = a(4) = 1.at n=37A118657
• Centered heptagonal prime numbers.at n=32A144974
• Centered heptagonal twin prime numbers.at n=13A144975
• Primes of the form n^2 - 10.at n=19A201313
• Primes p such that 16*p^2 + 10*p + 1 divides 2^p - 1.at n=24A231916
• Primes p with p + 2, prime(p) + 2 and prime(prime(p)) + 2 all prime.at n=12A236481
• Prime numbers containing the string 111.at n=30A243527
• Least positive integer k such that both k and k*n belong to the set {m>0: prime(m)+2 is prime with prime(prime(m)+2) = prime(prime(m))+6}.at n=14A261528
• Values of n such that n^2 + 5 is a triangular number (A000217).at n=12A276599
• Primes that can be generated by the concatenation in base 7, in descending order, of two consecutive integers read in base 10.at n=41A287309
• The first of three consecutive primes the sum of which is equal to the sum of three consecutive squares.at n=13A298223
• Primes having only {1, 6, 8} as digits.at n=24A385782
• Primes that are (product + sum) of a sequence of consecutive primes.at n=27A391078
• Prime numbersat n=6782