20341

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 81.at n=20A020420
• Primes p such that p, p+6, p+12, p+18 are all primes.at n=35A023271
• Numbers k such that 99*2^k+1 is prime.at n=40A032399
• Number of indecomposable binary [ n,5 ] codes without 0 columns.at n=13A034352
• Numbers k such that 285*2^k + 1 is prime.at n=26A053359
• Primes whose digits can be arranged in increasing cyclic order - to form a substring of 123456789012345678901234567890...at n=32A068710
• Initial term in sequence of four consecutive primes separated by 3 consecutive differences each <=6 (i.e., when d = 2, 4 or 6) and forming d-pattern = [6, 6, 4]; short d-string notation of pattern = [664].at n=16A078858
• Primes p such that the differences between the 5 consecutive primes starting with p are (6,6,4,2).at n=2A078966
• Primes such that a sum of any two adjacent digits is prime; first and last digits are considered adjacent.at n=46A086244
• Five-digit primes which use each of the decimal digits 0 through 4 exactly once.at n=3A109176
• Number of 3 X n {0,1}-matrices such that: (a) first and second row have a common 1, (b) second and third row have a common 1.at n=4A140961
• Primes congruent to 28 mod 61.at n=37A142826
• Numbers k such that (sum of base-2 digits of k) = (sum of base-10 digits of k) = 10.at n=34A152207
• Primes formed by rearranging five consecutive decimal digits (avoiding leading 0).at n=3A156119
• Number of ON cells at n-th stage of three-dimensional version of the cellular automaton A160117 using cubes.at n=16A160379
• Primes whose digits can be arranged as consecutive digits (more precisely, to form a substring of 0123456789).at n=24A177119
• Primes whose digits are a permutation of (0, ..., m) for some m.at n=3A187796
• Number of acute triangles, distinct up to congruence, on an n X n grid (or geoboard).at n=24A190021
• Primes of the form p(k)^2 + q(m)^2 with k > 0 and m > 0, where p(.) is the partition function (A000041), and q(.) is the strict partition function (A000009).at n=53A233346
• a(n) is the total number of pentagrams in a variant of pentagram fractal after n iterations.at n=12A256429