23689

Properties

Appears in sequences

• Primes that divide at least one term of Sylvester's sequence s = A000058: s(n+1) = s(n)^2 - s(n) + 1, s(0) = 2.at n=38A007996
• Numbers k such that the continued fraction for sqrt(k) has period 83.at n=21A020422
• a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A001950 (upper Wythoff sequence).at n=33A024689
• s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = A001950 (upper Wythoff sequence).at n=32A025122
• Denominators of continued fraction convergents to sqrt(719).at n=13A042385
• Numerators of continued fraction convergents to sqrt(750).at n=8A042444
• Primes for which the five closest primes are smaller.at n=13A075037
• Primes p such that q-p = 30, where q is the next prime after p.at n=27A124596
• Numbers with all different digits such that each digit leaves the same nonzero remainder when each is divided into the number.at n=11A152852
• Lesser of two Pythagorean primes for which the Pythagorean triangles have the same area.at n=16A157184
• Primes of the form x^2 + 5*y^2, where x and y=x+1 are consecutive natural numbers.at n=18A176608
• Primes of form n^2 + 10000.at n=22A256838
• Primes whose base-6 representation is a square when read in base 10.at n=9A267820
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 542", based on the 5-celled von Neumann neighborhood.at n=40A272811
• Centered 21-gonal primes.at n=9A276261
• a(n) is the least prime of the form prime(n)*p + prime(n+1)*q + prime(n+2)*r where p,q,r are consecutive primes.at n=50A340817
• Expansion of Product_{k>=1} 1 / (1 - x^k)^(7^(k-1)).at n=6A343352
• a(n) is the first prime p such that the concatenations of n consecutive primes, starting with p, in both forward and backward directions, are prime.at n=25A384958
• a(n) = greatest prime less than prime(n)*prime(n+1).at n=35A391805
• Prime numbersat n=2637