A107614 Consider the least number n such that n divided by pi(n) rounded is greater than any previous n; a(n) is the denominator of n/pi(n).

1, 6, 16, 42, 101, 280, 657, 1663, 4107, 10229, 25333, 63321, 159135, 399855, 1014612, 2582128, 6592653, 16898891, 43435899, 111985392, 289453817, 749973236, 1947409123, 5067034865, 13208284732, 34487824962, 90192879037

Offset: 2

Author

Jonathan Vos Post and Robert G. Wilson v, May 17 2005

Keywords

• nonn

Comments

Lim_{n->infinity} a(n+1)/a(n) ~ e.

Crossrefs

Cf. A000720, A107609, A107610.

Programs

Mathematica

f[n_] := Round[ n / PrimePi[ n]]; g[2] = 2; g[n_] := g[n] = Block[{k = PrimePi[E g[n - 1]]}, While[ f[k] < n, k++ ]; k]; Do[ Print[ g[ n]], {n, 2, 26}]; PrimePi[ g[ # ]] & /@ Range[2, 28]

Formula

a(n) = A000720(A107610(n)).