id:A089319 - OEIS Search Results

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Smallest k > 1 such that k^n followed by digit 1 is a prime.

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3, 2, 3, 3, 6, 2, 3, 6, 3, 11, 7, 2, 70, 2, 22, 18, 43, 3, 4, 649, 15, 3, 37, 2, 24, 13, 4, 8, 40, 77, 19, 22, 13, 24, 292, 48, 4, 2, 109, 792, 30, 4, 18, 5, 7, 90, 28, 138, 132, 891, 9, 25, 145, 2, 24, 9, 40, 28, 219, 165, 40, 41, 4, 13, 261, 24, 6, 30, 6, 154, 82, 22, 120, 2, 55 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`a(4) = 3 as concatenation of 3^4 and 1 = 811 is a prime. 161 is not a prime.`
	MATHEMATICA	`Do[k = 2; While[ !PrimeQ[10*k^n + 1], k++ ]; Print[k], {n, 1, 30}] (Propper)`
	CROSSREFS	`Cf. A089318.` `Adjacent sequences: A089316 A089317 A089318 this_sequence A089320 A089321 A089322` `Sequence in context: A058680 A070544 A087713 this_sequence A117231 A106151 A007888`
	KEYWORD	`base,nonn`
	AUTHOR	`Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 03 2003`
	EXTENSIONS	`Corrected and extended by Ryan Propper (rpropper(AT)stanford.edu), Jul 08 2005` `Further terms from David Wasserman (wasserma(AT)spawar.navy.mil), Sep 09 2005`

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Last modified October 7 14:39 EDT 2008. Contains 144666 sequences.

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