31609

Appears in sequences

• Strong pseudoprimes to base 70.at n=21A020296
• Strong pseudoprimes to base 99.at n=24A020325
• a(n) = (2*n+1)*(12*n+1).at n=36A033576
• Super-Poulet numbers: Poulet numbers whose divisors d all satisfy d|2^d-2.at n=19A050217
• Composite numbers k which divide A001045(k-1).at n=34A066488
• Pseudotwinprimes p+2 for primes p such that p+2 divides p^(p+2)+2 and p+2 is composite.at n=15A100873
• Odd composite numbers k for which k = A140607((k-1)/2).at n=5A140667
• Select all integers from the list (p(k)-k)/tau(k), k>=1; p = A000041, tau = A000005.at n=18A141669
• Sarrus numbers A001567 that are not Carmichael numbers A002997.at n=33A153508
• Nonprimes k such that 9*k divides 2^(k-1) - 1.at n=32A175521
• Pseudoprimes to base 2 of the form 4k+1.at n=36A178723
• Semiprimes p*q with p < q and 2^p (mod q) == 2^q (mod p).at n=30A179839
• An INVERT sequence for A010054.at n=19A181649
• Number of (w,x,y) with all terms in {0,...,n} and |w-x| + |x-y| != w+x+y.at n=31A213480
• Fermat pseudoprimes to base 2 with two prime factors.at n=19A214305
• Fermat pseudoprimes to base 2 of the form (6*k + 1)*(6*k*n + 1), where k, n are integers different from 0.at n=22A214607
• Fermat pseudoprimes to base 2 which are congruent to 1 (mod 8).at n=24A218483
• Fermat pseudoprimes to base 2 which are not Euler pseudoprimes to base 2.at n=19A227136
• Capped binary boundary codes for holeless strictly non-overlapping polyhexes (all orientations and rotations included).at n=35A258002
• Capped binary boundary codes for fusenes (all orientations and rotations included).at n=35A258012