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

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

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Formula

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

Mathematica

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

Prog

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

Crossrefs

Cf. A016088, A046024, A103592-A103600.

Sequence in context: A159321 A181077 A158873 * A245312 A018932 A111562

Adjacent sequences: A103588 A103589 A103590 * A103592 A103593 A103594

Keyword

nonn,more

Author

James R. Buddenhagen, Mar 28 2005

Extensions

a(7) from Robert Price, Dec 10 2013

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

Status

approved