21589

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 99.at n=16A020438
• Base-8 palindromes that start with 5.at n=35A043025
• Primes followed by a [10,2,10] prime difference pattern of A001223.at n=22A052376
• Primes which, although they have correct parity, are not in the prime number maze.at n=30A065123
• Engel expansion of zeta(7)=sum(i>0,1/i^7).at n=7A067915
• Numbers n such that [A070080(n), A070081(n), A070082(n)] is an isosceles integer triangle with integer area.at n=35A070145
• Primes which can be expressed as sum of distinct powers of 4.at n=31A077718
• Total number of parts equal to 1 in all plane partitions of n.at n=14A090539
• Primes p such that the sum of the digits of p is not prime, but the sum of each digit raised to the 4th power is prime.at n=16A091368
• Expansion of 1/(1 - 2*x - 21*x^2).at n=6A123012
• Number of base 29 circular n-digit numbers with adjacent digits differing by 5 or less.at n=4A125392
• Primes of the form 256 k + 85.at n=20A127593
• Take A163498(n) written in binary, insert a 0 before every 1. a(n) is the decimal equivalent of the result.at n=30A163499
• Primes p such that q = 2*p^2 - 1 and 2*p*q - 1 are also prime.at n=39A224990
• Odd integers k such that for every m >= 1 the numbers k*4^m - 1 have at least three prime factors, not necessarily distinct, and k*4^m - 1 has at least two-element covering set.at n=32A233552
• Primes whose base-4 representation also is the base 2-representation of a prime.at n=20A235461
• Primes p such that p^6 - p^5 + 1 and p^6 - p^5 - 1 are both primes.at n=5A243522
• Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 155", based on the 5-celled von Neumann neighborhood.at n=14A279252
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 179", based on the 5-celled von Neumann neighborhood.at n=14A279668
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 195", based on the 5-celled von Neumann neighborhood.at n=14A279751