21383

Properties

Appears in sequences

• Number of ordered quadruples of integers from [ 2,n ] with no global factor.at n=25A015638
• a(n) = prime(100*n).at n=23A031921
• a(n)=floor{square((1*n^0+1*n^1+2*n^2+4*n^3)/(1*n^0+2*n^1+1*n^2))}.at n=37A086863
• Number of truncated ST-pairs O(q^n).at n=24A094866
• Primes of the form 8*k-1 such that 4*k-1 and 16*k-1 are also primes.at n=20A101792
• Let p = prime(sigma(n)) and q = prime(phi(n)), then p is in the sequence if p-q = 6.at n=28A103176
• Least p=prime(k) for which A118123(k)=n.at n=21A117877
• Primes congruent to 25 mod 59.at n=39A142752
• Indices of records in A157190: prime(a(n)) can be written in more ways as pq-p-q (p,q, prime) than any smaller prime.at n=10A157191
• a(n) = 66*n^2 - 1.at n=17A158693
• Primes p such that 3*p+4, 5*p+6 and 7*p+8 are also prime.at n=23A173879
• Supersafe primes.at n=35A181841
• Number of -5..5 arrays x(0..n-1) of n elements with zero sum and no element more than one greater than the previous.at n=7A199844
• a(n) + a(n+2) = n^3.at n=35A206481
• Smallest number m such that A210659(m)=n.at n=11A210660
• Smallest prime k such that (k+p(1)) (k+p(2))...(k+p(n))/(p(n)#) is an integer.at n=15A215490
• Primes formed from concatenation of PrimePi(n) and prime(n).at n=26A236551
• Number of length n+4 0..2 arrays with no five consecutive elements with pattern ababa or abbba (with a!=b) and new values 0..2 introduced in 0..2 order.at n=6A244694
• T(n,k)=Number of length n+4 0..k arrays with no five consecutive elements with pattern ababa or abbba (with a!=b) and new values 0..k introduced in 0..k order.at n=34A244702
• Least positive integer k such that prime(prime(k)), prime(prime(k*n)), prime(p) and prime(q) form a 4-term arithmetic progression for some pair of primes p and q.at n=32A261462