271129

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 38.at n=26A031626
• (Provable) Sierpiński numbers: odd numbers n such that for all k >= 1 the numbers n*2^k + 1 are composite.at n=1A076336
• Prime values of n for which n*2^k + 1 is composite for all positive integers k.at n=0A137715
• Least k such that k*2^m + 1 has a covering set with precisely n primes.at n=0A206001
• Odd integers m such that for every integer k > 0, m*2^k+1 has a divisor in the set {3, 5, 7, 13, 17, 241}.at n=0A244561
• Odd numbers n not congruent to 5 mod 6 such that for all k >= 1 the numbers n*4^k + 1 are composite.at n=1A251057
• Least k such that k*2^m + 1 has a covering set of modulus 2*n, or 0 if no such value exists.at n=11A257647
• G.f. A(x) satisfies: Sum_{n>=0} Product_{k=1..n} (n+1-k)*x + k*A(x) = 1.at n=9A306087
• Prime numbersat n=23738