A063377 - OEIS

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A063377

Sophie Germain degree of n: number of iterations of n under f(k) = 2k+1 before we reach a composite number.

5, 2, 0, 4, 0, 1, 0, 0, 0, 3, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0 (list; graph; refs; listen; history; internal format)

	OFFSET	`2,1`
	COMMENTS	`a(n)>=1 means n is prime; a(n)>=2 means n is a Sophie Germain prime. Is the Sophie Germain degree always finite? Is it unbounded?`
	EXAMPLE	`a(2)=5 because 2, 5, 11, 23, 47 are prime but 95 is not.`
	CROSSREFS	`A005384, A063378.` `Cf. A093008, A093007.` `Sequence in context: A078110 A201528 A093814 * A196821 A147710 A153456` `Adjacent sequences: A063374 A063375 A063376 * A063378 A063379 A063380`
	KEYWORD	`nonn`
	AUTHOR	`Reiner Martin (reinermartin(AT)hotmail.com), Jul 14 2001`

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Last modified February 15 05:45 EST 2012. Contains 205694 sequences.