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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A090472 Primes in A089897.

Original entry on oeis.org

2, 5, 13, 103, 181, 3958349, 3745011198097903, 46240016923302054484370458782256657253421057237649913392609
Offset: 1

Views

Author

Cino Hilliard, Feb 01 2004

Keywords

Comments

The logarithmic integral can be computed in PARI: Li(x) = -eint1(log(1/x)).
Next term is A089897(858), which has 256 digits.
In fact the prime terms are for n=2, 3, 5, 9, 10, 26, 57, 202, 858, 1508, 1552, 2285, 4244, (5000). - Robert G. Wilson v

Crossrefs

Cf. A089897.

Programs

  • Mathematica
    Select[ Floor[ LogIntegral[ 2^Range[202]]], PrimeQ[ # ] &] (* Robert G. Wilson v, Nov 09 2005 *)
  • PARI
    lip(n) = forstep(x=1,n,1,y=floor(-eint1(log(1/2^x)));if(isprime(y),print1(y",")))

Extensions

Edited by David Wasserman, Nov 08 2005
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