19181

Properties

Appears in sequences

• Number of secondary alcohols (alkanols or alkyl alcohols C_n H_{2n+1} OH) with n carbon atoms.at n=14A000599
• Numbers k such that the continued fraction for sqrt(k) has period 71.at n=14A020410
• Smallest k>1 such that k(p-1)-1 is divisible by p^2, p=n-th prime.at n=33A039914
• Smaller of twin prime pairs in consecutively larger seas of composite numbers.at n=19A046928
• Primes whose consecutive digits differ by 7 or 8.at n=15A048419
• n is prime and is the concatenation of numbers n_1, n_2, n_3, in that order, with n_1 - n_2 = n_3. (Do not allow leading zeros for nonzero n_i.)at n=19A067861
• Smallest prime p such that sum of p and the next n-1 primes is a perfect square, or 1 if no such prime exists.at n=40A073887
• Primes p of the form k*(k + 1) - 1 such that p and p + 2 are twin primes.at n=18A088486
• Smallest prime of the form prime(k) concatenated with prime(k+n).at n=33A089782
• Primes of the form p^2 - p - 1, where p is prime.at n=15A091568
• Largest prime divisor of numerator of the n-th Artin's product.at n=32A119534
• Numerators of partial sums of Catalan numbers scaled by powers of 1/8.at n=5A120780
• Primes of the form p^k - p^(k-1) - 1, with p prime and k>1.at n=28A122395
• Primes p such that |100-p|, |1000-p|, |10000-p| and |100000-p| are also primes.at n=23A126021
• Smallest prime in a sequence of n consecutive primes which add to a perfect square.at n=39A132955
• Home primes whose homeliness is greater than 3.at n=32A133961
• Home primes whose homeliness is 4.at n=21A133962
• Lesser of twin primes isolated from neighboring primes by +- 10 (or more).at n=39A138063
• Primes congruent to 6 mod 59.at n=37A142733
• Primes congruent to 27 mod 61.at n=36A142825