A103596 Smallest prime p such that Sum_{primes q <= p} 1/q >= n/4.

2, 2, 3, 5, 11, 29, 73, 277, 1453, 11789, 169751, 5195977, 420055319, 118185163069

Offset: 1

Author

James R. Buddenhagen, Mar 28 2005

Keywords

• nonn

Comments

a(14) > pi(5*10^5). - Robert Price, Dec 10 2013

Crossrefs

Cf. A016088, A046024, A103591-A103600.

Programs

Mathematica

For[n = 1, n ≤ 17, n++, sum = 0; For[k = 1, k ≤ 10^6, k++, sum = sum + 1/Prime[k]; If[sum >= n/4, Print[Prime[k]]; Break[]]]]
Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/4, m++];
Prime[m], {n, 1, 14}] (* Robert Price, Mar 27 2019 *)

Extensions

a(1) added by Robert Price, Dec 10 2013

a(13)-a(14) from Robert Price, Dec 10 2013