Squarefree numbers (A005117) of the form p*q*r*s with prime factors p, q, r, s with q = 2*p + 1, r = 2*q + 1 and s = 2*r + 1.
A231968
Squarefree numbers (A005117) of the form p*q*r*s with prime factors p, q, r, s with q = 2*p + 1, r = 2*q + 1 and s = 2*r + 1.
Terms
- a(0) =2530a(1) =59455a(2) =4112125651a(3) =66487065301
External references
- oeis: A231968