51521

Properties

Appears in sequences

• Primes of the form 8*n^2 + 4*n + 1.at n=25A102130
• Primes of the form 50n^2 + 10n + 1.at n=15A154428
• Number of 6Xn -1,1 arrays such that the sum over i=1..6,j=1..n of i*x(i,j) is zero and rows are nondecreasing (ways to put n thrusters pointing east or west at each of 6 positions 1..n distance from the hinge of a south-pointing gate without turning the gate).at n=11A225313
• Primes p such that phi(p+1) = phi(phi(p-1)+1).at n=10A271655
• Numbers n such that n^2048 + (n+1)^2048 is prime.at n=38A274235
• Primes of the form k!9 + 1, where k!9 is the nonuple factorial number (A114806).at n=16A288371
• a(n) = a(n-1) + a(a(n-1) mod n) + 1, a(0) = 1.at n=37A308576
• Primes having only {1, 2, 5} as digits.at n=33A385773
• Primes p such that 2p-1 is a square and 2p+1 is also prime.at n=8A386995
• Prime numbersat n=5274