A140452 - OEIS

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A140452

2^(a(n))-1 contains an overpseudoprime divisor.

11, 22, 23, 25, 28, 29, 33 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`If p is a prime then p is in the sequence iff 2^p-1 is a composite number.`
	REFERENCES	`V. Shevelev, Overpsudoprimes, Mersenne Numbers and Wieferich Primes, http://arxiv.org/abs/0806.3412`
	CROSSREFS	`Cf. A141232, A137576, A005420, A049479.` `Sequence in context: A138838 A139337 A040110 * A048136 A180054 A166713` `Adjacent sequences: A140449 A140450 A140451 * A140453 A140454 A140455`
	KEYWORD	`nonn`
	AUTHOR	`Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jun 26 2008`

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Last modified February 14 20:13 EST 2012. Contains 205663 sequences.