28211

Properties

Appears in sequences

• Smallest prime p==3 (mod 8) such that Q(sqrt(-p)) has class number 2n+1.at n=36A002148
• a(n) = (1/C(n,0) + 1/C(n,1) + ... + 1/C(n,k))*L, where k = [ n/2 ], L = LCM{C(n,0), C(n,1),..., C(n,n)}.at n=13A025534
• Numerator of Sum_{k=0..n} 1/binomial(n,k).at n=13A046825
• Numerator of (1/n)*Sum_{k=0..n-1} 1/binomial(n-1,k) for n>0 else 0.at n=14A046878
• Largest prime dividing Sum_{k=0..n} k! * (n-k)!.at n=12A049413
• Primes of form Sum_{k=1..n} (prime(k)+1).at n=40A062736
• Numerator of Sum_{k=0..n} 1/C(2*n, 2*k).at n=6A100512
• Numerator of Sum_{k=0..[n/2]} 1/binomial(n,k).at n=13A100560
• To obtain a(n), take the n-th palindrome P = A002113(n) and concatenate it with the smallest palindrome Q such that PQ is a prime.at n=36A110786
• Primes p such that |100-p|, |1000-p|, |10000-p| and |100000-p| are also primes.at n=28A126021
• Primes of the form n^2 - 13.at n=16A154648
• Number of cusps in a class of degree-3n complex algebraic surfaces.at n=16A225018
• Number of Dyck paths of semilength n avoiding the pattern U^4 D^4 U D.at n=25A225691
• Primes in A065387 in the order of their appearance.at n=35A229264
• Primes which become palindromic primes when the digits are rotated once to the right.at n=19A235000
• Numerators of b(n) = b(n-1)/2 + 1/(2*n), b(0)=0.at n=14A242376
• Intersection of A251964, A252280 and A252281.at n=37A252283
• Primes of the form abs(-66n^3 + 3845n^2 - 60897n + 251831) in order of increasing nonnegative n.at n=14A272438
• Primes that can be generated by the concatenation in base 6, in ascending order, of two consecutive integers read in base 10.at n=15A287306
• SanD-68 primes p: such that p+d is also prime and sum of digits A007953(p(p+d)) = d, with d = 68.at n=1A307474