28031

Properties

Appears in sequences

• Truncated cube numbers.at n=10A005912
• Primes with 19 as smallest positive primitive root.at n=24A061331
• Primes of the form 8*k + 7 generated recursively. Initial prime is 7. General term is a(n) = Min_{p is prime; p divides 8*Q^2 - 1; p == 7 (mod 8)}, where Q is the product of the previous terms.at n=6A124985
• Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 110-111-011 pattern in any orientation.at n=11A146255
• Number of ways to place zero or more nonadjacent 1,0 1,1 2,1 3,1 4,2 4,3 polyhexes in any orientation on a planar nXnXn triangular grid.at n=6A155284
• Primes of the form k*(k+2)/3 - 2, k > 0.at n=37A162307
• Primes such that applying "reverse and add" twice produces two more primes.at n=16A174402
• Least prime k such that x' = k has n solutions, where x' is the arithmetic derivative (A003415) of x.at n=29A189559
• Number of (n+1)X(n+1) -8..8 symmetric matrices with every 2X2 subblock having sum zero and one or three distinct values.at n=8A211468
• Number of n-digit 7th powers.at n=34A216657
• Absolute discriminants of complex quadratic fields with 3-class group of type (3,3) and Hilbert 3-class field tower of exact length 2.at n=13A242864
• Absolute discriminants of complex quadratic fields with 3-class group of type (3,3) and 3-principalization type (2241).at n=7A247689
• Absolute discriminants of complex quadratic fields with 3-class group of type (3,3) whose second 3-class group is located on the sporadic part of the coclass graph G(3,2) outside of coclass trees.at n=20A247691
• a(n) is the least number that can be written in exactly n ways as p*q + q*r + p*r where (p,q,r) is an unordered triple of distinct primes.at n=29A356457
• Prime numbersat n=3059