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.

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A292775 a(n) = smallest prime q such that Sum_{primes p <= q} 1/sqrt(p) >= n.

Original entry on oeis.org

3, 7, 19, 41, 73, 113, 191, 271, 383, 509, 661, 859, 1069, 1307, 1601, 1931, 2287, 2687, 3119, 3583, 4093, 4657, 5279, 5881, 6607, 7351, 8167, 9001, 9851, 10837, 11867, 12899, 13967, 15161, 16361, 17627, 19031, 20389, 21821, 23297, 24917, 26557, 28279, 30059, 31891, 33647, 35617, 37607, 39779
Offset: 1

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Author

N. J. A. Sloane, Sep 30 2017

Keywords

Links

Crossrefs

Cf. A292774; A019529, A054040.

Programs

  • Maple
    Digits:=50;
s0:=0; k:=1; lisi:=[]; lisP:=[];
for i from 1 to 10000 do p:=ithprime(i);
s0:=s0+evalf(1/sqrt(p));
if s0 >= k then k:=k+1; lisi:=[op(lisi),i]; lisP:=[op(lisP),p]; fi;
od:
lisi; # A292774
lisP; # A292775
  • Mathematica
    f[n_]:=Block[{k=0, s=0}, While[sVincenzo Librandi, Oct 01 2017 *)

Formula

a(n) ~ prime(n)^2. - Benoit Cloitre, Oct 01 2017 [See link]
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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