

A105467


Number of irregular primes less than or equal to the 3^nth prime.


2



0, 0, 5, 22, 91, 286, 863, 2577, 7717, 23160, 69939, 209485, 627826, 1881554, 5645226, 16936048
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OFFSET

1,3


COMMENTS

Limit_{n>inf.} a(n)/3^n = 1e^(1/2).


LINKS

Table of n, a(n) for n=1..16.


MATHEMATICA

ip={ the list of irregular primes to 12 million }; Table[ Length[ Select[ip, # < Prime[3^n] &]], {n, 9}]


CROSSREFS

Cf. A038833, A105458, A105462.
Sequence in context: A081892 A128566 A097138 * A208736 A050185 A216597
Adjacent sequences: A105464 A105465 A105466 * A105468 A105469 A105470


KEYWORD

hard,nonn,more


AUTHOR

Robert G. Wilson v, Apr 07 2005


EXTENSIONS

Terms corrected and a(10)a(16) added by Amiram Eldar, Mar 05 2019


STATUS

approved



