id:A105465 - OEIS Search Results

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Number of irregular primes less than or equal to the 2^n-th prime.

+0
3

0, 0, 0, 1, 5, 15, 47, 95, 205, 405, 822, 1625, 3243, 6453, 12798, 25715, 51778, 103315, 206646 (list; graph; listen)

	OFFSET	`1,5`
	COMMENT	`Limit_{n->inf.} a(n)/2^n = 1-e^(-1/2).`
	MATHEMATICA	`ip={ the list of irregular primes to 12 million }; Table[ Length[ Select[ip, # < Prime[2^n] &]], {n, 19}]`
	CROSSREFS	`Cf. A105456, A105460.` `Sequence in context: A058425 A079798 A037504 this_sequence A089040 A126944 A077841` `Adjacent sequences: A105462 A105463 A105464 this_sequence A105466 A105467 A105468`
	KEYWORD	`hard,nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 07 2005`

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Last modified March 20 01:21 EDT 2010. Contains 173643 sequences.