31417

Appears in sequences

• Pisot sequence E(8,10), a(n) = floor( a(n-1)^2/a(n-2) + 1/2 ).at n=33A010916
• Strong pseudoprimes to base 29.at n=19A020255
• Strong pseudoprimes to base 34.at n=17A020260
• Strong pseudoprimes to base 42.at n=18A020268
• Strong pseudoprimes to base 61.at n=14A020287
• Strong pseudoprimes to base 70.at n=20A020296
• Strong pseudoprimes to base 83.at n=17A020309
• 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 16.at n=18A031604
• Super-Poulet numbers: Poulet numbers whose divisors d all satisfy d|2^d-2.at n=18A050217
• Numbers k such that phi(k) and cototient(k) are squares but k is not in A054755.at n=17A054756
• Composite numbers k which divide A001045(k-1).at n=33A066488
• Number of Cartesian lattice points in or on the circle x^2 + y^2 = 10^n.at n=4A068785
• A relationship between Pi and the Mandelbrot set. a(n) = number of iterations of z^2 + c that c-values -0.75 + x*i go through before escaping, where x = 10^(-n). Lim_{n->inf} a(n) * x = Pi.at n=4A097486
• Pell pseudoprimes: odd composite numbers n such that P(n)-Kronecker(2,n) is divisible by n.at n=33A099011
• Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only either two adjacent vertically or two adjacent horizontally.at n=11A145777
• Sarrus numbers A001567 that are not Carmichael numbers A002997.at n=32A153508
• Nonprimes k such that 9*k divides 2^(k-1) - 1.at n=31A175521
• Pseudoprimes to base 2 of the form 4k+1.at n=35A178723
• Semiprimes p*q with p < q and 2^p (mod q) == 2^q (mod p).at n=29A179839
• Fermat pseudoprimes to base 2 of the form (6*k - 1)*((6*k - 2)*n + 1), where k and n are positive integers.at n=24A210993