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A105467 Number of irregular primes less than or equal to the 3^n-th prime. 2
0, 0, 5, 22, 91, 286, 863, 2577, 7717, 23160, 69939, 209485, 627826, 1881554, 5645226, 16936048 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

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Last modified March 3 03:03 EST 2021. Contains 341756 sequences. (Running on oeis4.)