A085345 Least number x such that number of primes between phi(x) and x equals n.

2, 6, 12, 18, 24, 30, 50, 42, 48, 66, 60, 78, 96, 84, 90, 130, 108, 176, 114, 132, 156, 182, 150, 168, 186, 180, 216, 198, 228, 429, 210, 258, 308, 240, 276, 282, 270, 306, 294, 300, 354, 366, 336, 330, 384, 378, 396, 360, 432, 438, 622, 444, 390, 490, 474, 498

Offset: 1

Author

Labos Elemer, Jul 10 2003

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000720, A000010, A000203, A070803, A070804, A085341-A085347.

Programs

Maple

N:= 200: # for a(1)..a(N)
V:= Vector(N):
count:= 0:
for x from 1 while count < N do
  v:= numtheory:-pi(x) - numtheory:-pi(numtheory:-phi(x));
  if v >= 1 and v <= N and V[v] = 0 then
    V[v]:= x; count:= count+1;
  fi
od:
convert(V,list); # Robert Israel, Aug 23 2018

Formula

a(n)=Min{x; A085342(x)=n}