137149

Appears in sequences

• Strong pseudoprimes to base 4.at n=35A020230
• Strong pseudoprimes to base 11.at n=29A020237
• Pseudoprimes to bases 2 and 5.at n=20A083732
• Sarrus numbers k such that k-1 and k+1 have the same number of prime divisors (counted with multiplicity).at n=5A086806
• a(n)=12*sum(1<=i<=j<=k<=n,i*j/k).at n=23A088941
• Increasing gaps between 2-pseudoprimes (lower end).at n=14A175736
• Odd composite numbers m for which A000111(m) == (-1)^( (m-1)/2 ) (mod m).at n=27A180942
• Numbers m such that exactly half of the a such that 0<a<m and (a,m)=1 satisfy a^(m-1) == 1 (mod m).at n=24A191311
• Numbers in A191311 but not in A129521.at n=11A191592
• Smallest product of three distinct primes of the form n*k+1.at n=10A193873
• Smallest product of three distinct primes of the form n*k+1.at n=21A193873
• Numbers that occur more than once in A193873, in order of appearance.at n=4A194263
• Odd non-Carmichael numbers with increasing numbers of bases to which they are pseudoprimes.at n=27A194946
• Pseudoprimes divisible by a smaller pseudoprime.at n=10A215150
• Fermat pseudoprimes to base 2 of the form m*n^2 + (11*m - 23)*n + 19*m - 49, where m, n >= 0.at n=35A215326
• Fermat pseudoprimes to base 2 with three prime factors.at n=37A215672
• Fermat pseudoprimes to base 2 with three prime factors divisible by a smaller Fermat pseudoprime to base 2.at n=1A215944
• Composite integers k satisfying 2^d == 2^(k/d) (mod k) for all d|k and that are not Super-Poulet (A050217).at n=3A291602
• Odd numbers k > 1 such that 2^((k-1)/2) == -(2/k) = -A091337(k) (mod k), where (2/k) is the Jacobi (or Kronecker) symbol.at n=8A306310
• a(n) is the smallest n-gonal number that is a Fermat pseudoprime to base 2 (A001567), or -1 if no such number exists.at n=34A371759