30121

Appears in sequences

• Euler pseudoprimes: composite numbers n such that 2^((n-1)/2) == +-1 (mod n).at n=23A006970
• Composite numbers k such that k == +-1 (mod 8) and 2^((k-1)/2) == 1 (mod k).at n=17A006971
• Expansion of 1 / ((1-x) * (1-3*x) * (1-12*x)).at n=4A016217
• Strong pseudoprimes to base 62.at n=25A020288
• Strong pseudoprimes to base 75.at n=29A020301
• Number of partitions in parts not of the form 17k, 17k+3 or 17k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 7 are greater than 1.at n=44A035964
• Euler-Jacobi pseudoprimes: 2^((n-1)/2) == (2 / n) mod n, where (2 / n) is a Jacobi symbol.at n=19A047713
• Number of step cyclic shifted sequence structures using exactly five different symbols.at n=11A056437
• Composite numbers k which divide A001045(k-1).at n=31A066488
• Sarrus numbers n (A001567) which satisfy mu(n) = -1 and which are not Super-Poulet numbers (A050217).at n=19A074380
• Sarrus numbers with more than 2 distinct prime factors.at n=22A080747
• Terms of sequence A005150 interpreted as numbers written in base 4 (written here in base ten).at n=6A098097
• Pseudotwinprimes p+2 for primes p such that p+2 divides p^(p+2)+2 and p+2 is composite.at n=14A100873
• Sarrus numbers A001567 that are not Carmichael numbers A002997.at n=30A153508
• Nonprimes k such that 9*k divides 2^(k-1) - 1.at n=29A175521
• Pseudoprimes to base 2 of the form 4k+1.at n=33A178723
• 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=20A214607
• Fermat pseudoprimes to base 2 with three prime factors.at n=19A215672
• Composite integers k such that 2^k == 2 (mod k*(k+1)).at n=12A217465
• Number of n element 0..1 arrays with each element the minimum of 7 adjacent elements of a random 0..1 array of n+6 elements.at n=29A217838