20269

Properties

Appears in sequences

• a(0) = 13; for n > 0, a(n) is the greatest prime factor of PreviousPrime(a(n-1))*a(n-1)-1 where PreviousPrime(prime(k))=prime(k-1).at n=6A031442
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 88 ones.at n=25A031856
• Primes p whose period of reciprocal equals (p-1)/9.at n=13A056214
• Luhn primes: primes p such that p + (p reversed) is also a prime.at n=35A061783
• Prime numbers p such that A022559(p) is a multiple of A000720(p).at n=11A088542
• Primes from merging of 5 successive digits in decimal expansion of exp(2).at n=16A105001
• Numbers k such that (11^k - 5^k)/6 is prime.at n=7A128347
• Primes congruent to 32 mod 59.at n=36A142759
• Primes congruent to 17 mod 61.at n=35A142815
• Primes congruent to 34 mod 71.at n=32A154624
• Pairs of consecutive primes {p,q} for which the numbers of distinct residues of all factorials mod p and mod q coincide.at n=32A210242
• Number of set partitions of [n] such that all absolute differences between least elements of consecutive blocks and between consecutive elements within the blocks are not larger than seven.at n=9A287586
• Rounded value of z(n)*prime(n), where z(n) = imaginary part of n-th nontrivial zero of the Zeta function and prime(n) = n-th prime.at n=38A342756
• Primes p such that p-2 is the product of two emirps.at n=30A345198
• Array read by ascending antidiagonals: A(n, k) = n!*[x^(n-1)] Li(-k, 1 - exp(-4*x))/(4*x*cosh(x)), where Li(n, z) is the polylogarithm function.at n=41A345393
• Primes that are the sum of some number of consecutive prime squares.at n=18A376916
• Primes having only {0, 2, 6, 9} as digits.at n=23A386052
• Prime numbersat n=2291