20173

Properties

Appears in sequences

• A variant of the cuban primes: primes p = (x^3 - y^3)/(x - y) where x = y + 2.at n=15A002648
• a(n) = T(2n,n-1), T given by A026769.at n=6A026771
• Greatest number in row n of array T given by A026769.at n=14A027238
• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 94.at n=0A031682
• Numbers n such that binomial(2n, n) - 1 is prime.at n=42A066726
• n is prime and is the concatenation of numbers n_1, n_2, n_3, in that order, with n_1 - n_2 = n_3. (Do not allow leading zeros for nonzero n_i.)at n=20A067861
• Primes of the form k^2 + 9.at n=19A138353
• Primes congruent to 43 mod 61.at n=36A142841
• Primes of the form Sum_{k=1..m} (m^k mod (m+k)).at n=19A156557
• a(n) = 12*n^2 + 1.at n=41A158480
• Primes p such that p^3-p^2-1 and p^3-p^2+1 are prime.at n=31A160858
• Primes from twin primes by taking the factorial of each digit and adding them up.at n=56A165934
• One third of product plus sum of six consecutive nonnegative numbers.at n=4A166943
• Primes of the form n^2+number of divisors of n^2.at n=22A188665
• 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=52A233346
• Primes p with A047967(p) also prime.at n=15A236418
• Number of length 3+2 0..n arrays with the sum of second differences multiplied by some arrangement of +-1 equal to zero.at n=9A250562
• Number of (n+2)X(n+2) 0..1 arrays with every 3X3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=5A254899
• Number of (n+2)X(6+2) 0..1 arrays with every 3X3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=5A254905
• Number of (6+2)X(n+2) 0..1 arrays with every 3X3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=5A254912