121574

Appears in sequences

• a(n) = phi(2^n+1)/(2*n).at n=22A069925
• A Jacobsthal Fibonacci product: a(n) = (2^n + 2*(-1)^n)*Fibonacci(n-1)/3.at n=12A093044
• Unique prime factors of 2^n+1 are of the form kn+1. These are the values for k.at n=25A098268
• A000799(n) - A064355(n).at n=68A114699
• a(n) = ((2^prime(n+2)-2)/prime(n+2))/3, where n >= 1.at n=6A145756
• Number of 2-elements orbits of S3 action on irreducible polynomials of degree 3n, n > 0, over GF(2).at n=22A165920
• Least positive number k such that k*p+1 divides 2^p+1 where p is prime(n), or 0 if no such number exists.at n=8A185343
• Sets with a congruence property.at n=10A262590