id:A166546 - OEIS Search Results

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Natural numbers n such that d(n) + 1 is prime.

+0
3

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	OFFSET	`1,2`
	COMMENT	`Natural numbers n such that d(d(n)+1)= 2. [From Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Oct 26 2009]` `The complement is the union of A001248, A030514, A030516, A030626, A030627, A030629, A030631, A030632, A030633 etc. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 26 2009]`
	FORMULA	`{1} U A000040 U A030513 U A030515 U A030628 U A030630 U A030634 U A030636 U A137485 U A137491 U A137493 U ... [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 26 2009]`
	CROSSREFS	`Cf. A000005` `Cf. A073915. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 26 2009]` `Sequence in context: A028761 A028809 A028785 this_sequence A167759 A028812 A039251` `Adjacent sequences: A166543 A166544 A166545 this_sequence A166547 A166548 A166549`
	KEYWORD	`nonn`
	AUTHOR	`Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Oct 16 2009`

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Last modified November 25 08:46 EST 2009. Contains 167481 sequences.

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