cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 10 results.

A046024 a(n) = smallest k such that Sum_{ i = 1..k } 1/prime(i) exceeds n.

Original entry on oeis.org

1, 3, 59, 361139, 43922730588128390
Offset: 0

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Author

Keywords

Comments

The corresponding primes prime(a(n)) are in A016088.
Index m for which the prime harmonic number p[ m ] := Sum[ 1/Prime[ k ],{k,1,m} ] >= n.

Crossrefs

Cf. A024451/A002110 for Sum_{i = 1..n} 1/prime(i).

Programs

  • Mathematica
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) <= n, m++];
    m, {n, 0, 4}] (* Robert Price, Mar 27 2019 *)
  • PARI
    a(n)=my(t); forprime(p=2,, t+=1./p; if(t>n, return(primepi(p)))) \\ Charles R Greathouse IV, Apr 29 2015

Formula

From Jonathan Sondow, Apr 17 2013: (Start)
a(n) = A000720(A016088(n)) = A000720(A096232(n))+1.
a(n) = e^(e^(n + O(1))), see comment in A223037. [corrected by Charles R Greathouse IV, Aug 22 2013] (End)
a(n) = A103591(2*n). - Michel Marcus, Aug 22 2013

Extensions

a(4) found by Tomás Oliveira e Silva (tos(AT)det.ua.pt), using the fourth term of A016088. - Dec 14 2005
a(0) from Jonathan Sondow, Apr 16 2013

A103600 Smallest prime p such that Sum_{primes q <= p} 1/q >= n/6.

Original entry on oeis.org

2, 2, 2, 3, 3, 5, 7, 13, 29, 53, 109, 277, 809, 2741, 11789, 64663, 483281, 5195977, 85861889, 2358926351, 118185163069, 12041724518809
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Crossrefs

Programs

  • Mathematica
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/6, m++];
    Prime[m], {n, 1, 17}] (* Robert Price, Mar 27 2019 *)

Extensions

a(1), a(2), a(4) added for correctness, and a(19-21) included by Martin Raab, Mar 31 2009
a(22) from Charles R Greathouse IV, Jan 18 2012

A103592 a(n) is the smallest prime p such that Sum_{primes q <= p} 1/q >= n/2.

Original entry on oeis.org

2, 5, 29, 277, 11789, 5195977, 118185163069, 1801241230056600523
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Crossrefs

Programs

  • Mathematica
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/2, m++];
    Prime[m], {n, 1, 8}] (* Robert Price, Mar 27 2019 *)

Extensions

a(7)-a(8) from Martin Raab, Aug 24 2008
a(7) corrected by Martin Raab, Mar 31 2009

A103599 Smallest number m such that Sum_{k=1..m} 1/prime(k) >= n/6.

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 4, 6, 10, 16, 29, 59, 140, 400, 1413, 6467, 40261, 361139, 4990906, 114916199, 4833601540
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Comments

a(22) > 5*10^10. - Robert Price, Dec 10 2013

Crossrefs

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/6, Print[k]; Break[]]]] (* Robert Price, Dec 09 2013 *)
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/6, m++];
    m, {n, 1, 17}] (* Robert Price, Mar 27 2019 *)

Extensions

a(2)-a(4) and a(19)-a(21) added by Robert Price, Dec 10 2013

A103593 Smallest number m such that Sum_{k=1..m} 1/prime(k) >= n/3.

Original entry on oeis.org

1, 2, 3, 6, 16, 59, 400, 6467, 361139, 114916199
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Comments

a(n) <= e^(e^(n/3)), therefore a(10) < 1492725701441. - Stefan Steinerberger, Mar 18 2006
a(11) > 5*10^10. - Robert Price, Dec 10 2013

Crossrefs

Programs

  • Mathematica
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/3, m++];
    m, {n, 1, 10}] (* Robert Price, Mar 27 2019 *)

Extensions

a(10) from Robert Price, Dec 10 2013

A103594 Smallest prime p such that Sum_{primes q <= p} 1/q >= n/3.

Original entry on oeis.org

2, 3, 5, 13, 53, 277, 2741, 64663, 5195977, 2358926351, 12041724518809, 1801241230056600523
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Crossrefs

Programs

  • Mathematica
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/3, m++];
    Prime[m], {n, 1, 10}] (* Robert Price, Mar 27 2019 *)

Extensions

a(10) from Robert Price, Dec 10 2013
a(11) and a(12) copied from A103600(22) and A016088(4), respectively, by Jon E. Schoenfield, Feb 01 2020

A103595 Smallest number m such that Sum_{k=1..m} 1/prime(k) >= n/4.

Original entry on oeis.org

1, 1, 2, 3, 5, 10, 21, 59, 231, 1413, 15474, 361139, 22347214, 4833601540
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Comments

a(15) > 5*10^10. - Robert Price, Dec 10 2013

Crossrefs

Programs

  • Mathematica
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/4, m++];
    m, {n, 1, 14}] (* Robert Price, Mar 27 2019 *)

Extensions

a(1) and a(13)-a(14) from Robert Price, Dec 10 2013

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

Original entry on oeis.org

2, 2, 3, 5, 11, 29, 73, 277, 1453, 11789, 169751, 5195977, 420055319, 118185163069
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Comments

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

Crossrefs

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

A103597 Smallest number m such that Sum_{k=1..m} 1/prime(k) >= n/5.

Original entry on oeis.org

1, 1, 2, 2, 3, 5, 7, 13, 25, 59, 170, 644, 3402, 27178, 361139, 8947437, 474314304
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Comments

a(18) > 5*10^10. - Robert Price, Dec 10 2013

Crossrefs

Programs

  • Mathematica
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/5, m++];
    m, {n, 1, 17}] (* Robert Price, Mar 27 2019 *)

Extensions

a(2)-a(3) and a(16)-a(17) from Robert Price, Dec 10 2013

A103598 Smallest prime p such that Sum_{primes q <= p} 1/q >= n/5.

Original entry on oeis.org

2, 2, 3, 3, 5, 11, 17, 41, 97, 277, 1013, 4789, 31627, 314723, 5195977, 159490147, 10443979657
Offset: 1

Views

Author

James R. Buddenhagen, Mar 28 2005

Keywords

Comments

a(18) > pi(5*10^10). - Robert Price, Dec 10 2013

Crossrefs

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/5, Print[Prime[k]]; Break[]]]]
    Table[m = 1; s = 0; While[(s = s + 1/Prime[m]) < n/5, m++];
    Prime[m], {n, 1, 17}] (* Robert Price, Mar 27 2019 *)

Extensions

a(1)-a(2) and a(16)-a(17) from Robert Price, Dec 10 2013
Showing 1-10 of 10 results.