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A090472 Primes in A089897. 1
2, 5, 13, 103, 181, 3958349, 3745011198097903, 46240016923302054484370458782256657253421057237649913392609 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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

LINKS

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

MATHEMATICA

Select[ Floor[ LogIntegral[ 2^Range[202]]], PrimeQ[ # ] &] (* Robert G. Wilson v, Nov 09 2005 *)

PROG

(PARI) lip(n) = forstep(x=1, n, 1, y=floor(-eint1(log(1/2^x))); if(isprime(y), print1(y", ")))

CROSSREFS

Cf. A089897.

Sequence in context: A100843 A082101 A158712 * A120266 A230518 A241248

Adjacent sequences:  A090469 A090470 A090471 * A090473 A090474 A090475

KEYWORD

nonn

AUTHOR

Cino Hilliard, Feb 01 2004

EXTENSIONS

Edited by David Wasserman, Nov 08 2005

STATUS

approved

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Last modified July 25 03:53 EDT 2021. Contains 346283 sequences. (Running on oeis4.)