A159031 - OEIS

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A159031

Primes of the form "1 [0]_n 7" - with zeros between 1 and 7.

17, 107, 10007, 100000007, 1000000007, 1000000000000000000000007, 1000000000000000000000000000000000000000000000000000000000007 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`The next term, a(8), has 111 digits. [From Harvey P. Dale, Nov 12 2011]`
	LINKS	`Dario Alejandro Alpern, Factorization using the Elliptic Curve Method.`
	EXAMPLE	`1000000000000000000000007 is a prime with 23 zeros between 1 and 7.`
	MATHEMATICA	`Do[ If[ PrimeQ[10^n + 7], Print[10^n + 7]], {n, 100}] [From Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 05 2009]` `Select[Table[FromDigits[Join[{1}, PadRight[{}, n, 0], {7}]], {n, 0, 120}], PrimeQ] (* From Harvey P. Dale, Nov 12 2011 *)`
	CROSSREFS	`Cf. A088274. [From Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 05 2009]` `Sequence in context: A007682 A125327 A126485 * A080441 A135400 A052254` `Adjacent sequences: A159028 A159029 A159030 * A159032 A159033 A159034`
	KEYWORD	`nonn`
	AUTHOR	`Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Apr 02 2009`
	EXTENSIONS	`a(7) from Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 05 2009`

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Last modified February 14 11:17 EST 2012. Contains 205623 sequences.