21683

Properties

Appears in sequences

• Primes that remain prime through 3 iterations of function f(x) = 3x + 4.at n=14A023278
• Primes that remain prime through 4 iterations of the function f(x) = 3x + 4.at n=1A023308
• Numerators of continued fraction convergents to sqrt(603).at n=7A042156
• a(1) = 2; a(n) is the smallest prime > a(n-1) such that a(n) + a(n-1) is a square.at n=21A062064
• A nonsense sequence (not well-defined).at n=25A089174
• Negative of column k=3 sequence of array A103728.at n=13A103730
• K-bit primes p such that p-2^i and p+2^i are composite for 0<=i<=K-1.at n=11A153352
• Primes of the form Sum_{k=1..m} (m^k mod (m-k+1)).at n=41A156559
• Primes which are the sum of 6 consecutive triangular numbers A000217.at n=11A159071
• Noncomposite numbers in the eastern ray of the Ulam spiral as oriented on the March 1964 cover of Scientific American.at n=21A168022
• Primes p such that 12*p^2-1 and 16*p^3-1 are also primes.at n=32A193051
• a(0) = 0; a(n+1) = 2*a(n) + k where k = 0 if prime(n+2)/prime(n+1) > prime(n+1)/prime(n), otherwise k = 1.at n=16A215411
• a(n) = prime(k) with k = n^2 + prime(n)^2.at n=14A243892
• Odd numbers m that are neither of the form p + 2^k nor of the form p - 2^k with 2^k < m, k >= 1, and p prime.at n=27A255967
• Prime numbers that are the sum of one or more consecutive triangular numbers.at n=40A269414
• The set S of primes q satisfying certain conditions (see Müller, 2010 for precise definition).at n=7A275739
• Prime numbersat n=2434