id:A091189 - OEIS Search Results

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Primes of the form 20*R_n + 1, where R_n is the repunit (A002275) of length n.

+0
2

2221, 222222222222222221, 22222222222222222222222222222222222222222222222222222222222222222222222222222222\ 22222222222222222221 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Primes of the form 222...221.` `The number of 2's in each term is given by the corresponding term of A056660 and so the first term too large to include above is 222...2221 (with 120 2's).`
	CROSSREFS	`Cf. A056660 (corresponding n).` `Cf. A051200, A004022, A093176, A093177, A089346.` `Sequence in context: A138079 A092992 A166580 this_sequence A046443 A043500 A118116` `Adjacent sequences: A091186 A091187 A091188 this_sequence A091190 A091191 A091192`
	KEYWORD	`bref,nonn`
	AUTHOR	`Rick L. Shepherd (rshepherd2(AT)hotmail.com), Feb 22 2004`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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