21295

Appears in sequences

• Expansion of log(1+x)*cos(tanh(x)).at n=11A009409
• Integer part of ((4th elementary symmetric function of 1,2,..,n)/(2nd elementary symmetric function of 1,2,...,n)).at n=31A024173
• Numerators of continued fraction convergents to sqrt(154).at n=9A041282
• Numerators of continued fraction convergents to sqrt(616).at n=9A042182
• Write fundamental unit for real quadratic field of discriminant n as x + y*omega; sequence gives values of x for n == 2 mod 4.at n=31A053371
• Numbers k such that 2^k - prime(k)^2 is prime.at n=16A116999
• Number of n X n binary arrays symmetric about main diagonal with all ones connected in a 3X2 elbow 1,1 1,2 1,3 2,3 in any orientation.at n=8A145946
• Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected in a 3 X 2 elbow 1,1 1,2 1,3 2,3 in any orientation.at n=18A145948
• Number of n X n binary arrays symmetric about the diagonal and under 90-degree rotation with all ones connected in a 3 X 2 elbow 1,1 1,2 1,3 2,3 in any orientation.at n=19A145948
• a(n) = 14*n^2 + 1.at n=38A158482
• a(n) = 44*n^2 - 1.at n=21A158628
• Numbers k such that 13 is the largest prime factor of k^2 - 1.at n=32A181451
• a(n) = A057641(A094348(n)).at n=31A181852
• Conjectured lower bounds for the Riemann hypothesis function floor(H(k) + exp(H(k))*log(H(k))) - sigma(k).at n=20A222761
• The 240-degree spoke (or ray) of a hexagonal spiral of Ulam.at n=42A244805
• Number k such that k^2 + 1 = p*q*r where p,q,r are distinct primes and the sum p+q+r is a perfect square.at n=13A261529
• L.g.f.: Sum_{n>=1} (x - x^(2*n-1))^(2*n-1) / (2*n-1).at n=45A293597
• Bases in which 11 is a unique-period prime.at n=30A306076