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A105467

Number of irregular primes less than or equal to the 3^n-th prime.

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

OFFSET

1,3

COMMENTS

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

LINKS

MATHEMATICA

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

CROSSREFS

KEYWORD

hard,nonn,more

AUTHOR

EXTENSIONS

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

STATUS

approved

URL: https://oeis.org/A105467