A103591 Smallest number m such that Sum_{k=1..m} 1/prime(k) >= n/2.

1, 3, 10, 59, 1413, 361139, 4833601540, 43922730588128390

Offset: 1

Author

James R. Buddenhagen, Mar 28 2005

Keywords

• nonn
• more

Crossrefs

Cf. A016088, A046024, A103592-A103600.

Programs

Mathematica

Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/2, m++];
m, {n, 1, 5}] (* Robert Price, Mar 27 2019 *)

PARI

a(n) = my(s = 0, k = 1); while ((s += 1/prime(k)) < n/2, k++); k \\ Michel Marcus, Aug 22 2013

Formula

a(2n) = A046024(n). - Michel Marcus, Aug 22 2013

Extensions

a(7) from Robert Price, Dec 10 2013

a(8) derived from A046024 by Robert Price, Dec 10 2013