19661

Properties

Appears in sequences

• Record gaps between primes (upper end) (compare A002386, which gives lower ends of these gaps).at n=12A000101
• Smallest prime p such that there is a gap of 2n between p and previous prime.at n=25A001632
• a(1) = a(2) = 1, a(2n + 1) = 2*a(2n) and a(2n) = 2*a(2n - 1) + (-1)^n.at n=15A016029
• Numbers k such that the continued fraction for sqrt(k) has period 91.at n=10A020430
• Smallest nontrivial extension of n-th square which is a prime.at n=13A030685
• Upper prime of a record difference between it and the second prime before it.at n=15A031134
• Prime islands: for n >= 2, a(n) = least prime whose adjacent primes are exactly 2n apart; a(1) = 3 by convention.at n=35A046931
• Difference between length (A005341) and sum of digits (A004977) of n-th term in Look and Say Sequence (A005150).at n=36A056635
• a(n) = 2*p + 2*n - 1, where p is the least prime such that next_prime(2*p) - 2*p = 2*n - 1.at n=19A059847
• Upper ends of record prime gaps under consideration of the prime number theorem.at n=12A060771
• Group the natural numbers such that the n-th group contains n terms and the group sum is the smallest possible prime: (2), (1, 4), (3, 5, 9), (6, 7, 8, 10), (11, 12, 13, 14, 17), (15, 16, 18, 19, 20, 21), ... Sequence gives group sums.at n=33A075345
• Expansion of 1/(1+x-2*x^3).at n=29A077973
• Expansion of (1-x)/(1+2*x+x^2+2*x^3).at n=14A078066
• Smallest prime which occurs exactly n times in the sequence A086527.at n=25A086528
• Aloof primes: Total distance between prime and neighboring primes sets record.at n=17A096265
• Primes of the form [prime(n)*prime(n+1)+p]/2 with increasing p.at n=41A100558
• Smallest prime number that ends a prime gap of at least 2n.at n=25A100965
• Smallest prime number that ends a prime gap of at least 2n.at n=24A100965
• Smallest prime number that ends a prime gap of at least 2n.at n=23A100965
• Smallest prime number that ends a prime gap of at least 2n.at n=22A100965