27479

Properties

Appears in sequences

• Primes that remain prime through 3 iterations of the function f(x) = 2*x + 1.at n=20A023272
• a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n -1 <= 2^(p+1), with a(1) = 1, a(2) = 3, and a(3) = 4.at n=14A049977
• Primes starting a Cunningham chain of the first kind of length 4.at n=15A059763
• Primes A005382(n) + A005384(n) - 1 with a twin prime A005382(n) + A005384(n) + 1.at n=33A099109
• Primes of the form 4*k-1 such that 8*k-1, 16*k-1 and 32*k-1 are also primes.at n=6A101795
• Smallest primes starting a complete three iterations Cunningham chain of the first or second kind.at n=24A110025
• Primes p such that p + 2, 18*p^2 + 1, and 18*(p+2)^2 + 1 are all primes.at n=12A115272
• Numerators of convergents to Magata's constant.at n=8A118203
• Triangle read by rows: a(m,m) = 1, for all m. For n < m, a(m,n) = a(m-1,n) + (sum of all terms in rows 1 through m-1).at n=32A159924
• The first member of a twin prime pair whose sum equals the sums of two consecutive smaller pairs of twin primes.at n=39A225943
• a(n) = the first member of a twin prime pair whose sum equals the sums of n consecutive pairs of twin primes.at n=38A226719
• Primes p such that 2*p^3 + 1 and 2*p^3 + 3 are also primes.at n=19A252042
• a(1)=2; thereafter a(n) is the smallest prime > a(n-1) that is not a factor of any 1+A, where A is a product of one or more distinct earlier terms.at n=17A260388
• Numbers k for which 2*4^k - 27 is prime.at n=10A275767
• a(n) = Sum_{i=0..floor(q(n)/3)} binomial(n-3*(i+1), q(n)-3*i) with q(n) = ceiling((n-3)/2).at n=17A366107
• a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-3*k-1,n-3*k).at n=9A371758
• Prime numbersat n=3002