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A105456 Number of irregular primes less than 2^n. 2
0, 0, 0, 0, 0, 2, 5, 9, 28, 64, 124, 225, 408, 763, 1378, 2566, 4803, 9005, 16948, 32300, 61408, 116688, 222093, 424411, 812236, 1556827, 2991345, 5756015, 11089585, 21403049 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Table of n, a(n) for n=1..30.

MATHEMATICA

ip={ the list of irregular primes to 12 million }; Table[ Length[ Select[ip, # < 2^n &]], {n, 23}]

CROSSREFS

Cf. A007053, A105460, A105465.

Sequence in context: A094600 A139796 A086586 * A128565 A151952 A090291

Adjacent sequences:  A105453 A105454 A105455 * A105457 A105458 A105459

KEYWORD

hard,nonn,more

AUTHOR

Robert G. Wilson v, Apr 07 2005

EXTENSIONS

a(23) corrected and a(24)-a(40) added by Amiram Eldar, Mar 05 2019

STATUS

approved

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Last modified September 28 22:03 EDT 2020. Contains 337417 sequences. (Running on oeis4.)