41665

Appears in sequences

• Sarrus numbers n (A001567) which satisfy mu(n) = -1 and which are not Super-Poulet numbers (A050217).at n=23A074380
• Sarrus numbers with more than 2 distinct prime factors.at n=28A080747
• a(n) = (3 + 2*n + 6*n^2 + 4*n^3)/3.at n=31A166464
• Nonprimes k such that 9*k divides 2^(k-1) - 1.at n=37A175521
• Pseudoprimes to base 2 of the form 4k+1.at n=43A178723
• Number of n X 5 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 1 vertically.at n=9A207166
• 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=28A210993
• 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=26A214607
• Fermat pseudoprimes to base 2 of the form m*n^2 + (11*m - 23)*n + 19*m - 49, where m, n >= 0.at n=24A215326
• Fermat pseudoprimes to base 2 with three prime factors.at n=23A215672
• Fermat pseudoprimes to base 2 divisible by 5.at n=10A216023
• Fermat pseudoprimes to base 2 which are congruent to 1 (mod 8).at n=29A218483
• Fermat pseudoprimes to base 2 which are not Euler pseudoprimes to base 2.at n=22A227136
• Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0.at n=24A283887
• Poulet numbers which are not super-Poulet numbers.at n=28A306487
• 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=19A371759