22571

Properties

Appears in sequences

• Numbers p from A001125 such that 2*p-3 is prime.at n=29A063939
• a(1) = 1; then primes associated with A091850.at n=38A091851
• Primes of the form (k+1)*prime(k) + k*prime(k+1).at n=19A097241
• a(n) = Sum{0<=k<=n} binomial(n+k, n-k) * k! / (floor(k/2)! * floor((k+2)/2)!).at n=9A190908
• Construct sequences P,Q,R by the rules: Q = first differences of P, R = second differences of P, P starts with 1,3,9, Q starts with 2,6, R starts with 4; at each stage the smallest number not yet present in P,Q,R is appended to R. Sequence gives P.at n=45A225385
• Primes p such that b=2*p+1 is semiprime, c=2*b+1 is 3-almost prime and d=2*c+1 is 4-almost prime.at n=19A235646
• Primes p = prime(n): such that p.n and n.p both are prime, where (.) indicates concatenation.at n=33A243886
• Primes of the form (k^2+2)/6.at n=43A245045
• Primitive prime factors of the cyclotomic polynomial sequence Phi(5,k) in the order in which they occur.at n=33A256153
• Number of n X 3 0..1 arrays with every element equal to 0, 1, 3, 4, 5 or 6 king-move adjacent elements, with upper left element zero.at n=8A299047
• Number of connected 2n-regular loopless multigraphs with five nodes.at n=20A324221
• Numbers that cannot be expressed as the sum of one or more numbers without any repeated digits.at n=17A342080
• Indices of records in A347113.at n=29A347308
• Prime numbersat n=2523