A178406 - OEIS

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A178406

Numbers n such that 10^n - 41 is prime.

2, 6, 8, 12, 14, 47, 88, 130, 414, 1388, 1932, 4106, 4412, 12870, 22956, 23932, 27312, 35316, 37169, 43873, 150029 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,1`
	COMMENTS	`The next term, if one exists, is >100000. - Robert Price, Apr 25 2011` `a(22) > 2.5*10^5. - Robert Price, Apr 12 2015`
	LINKS	`Table of n, a(n) for n=1..21.` `Makoto Kamada, Near-repdigit numbers of the form AA...AABA.` `Makoto Kamada, Prime numbers of the form 99...9959.` `Index entries for primes involving repunits.`
	EXAMPLE	`10^6 - 41 = 999959 which is a prime number.`
	MATHEMATICA	`m=1000; For[n=1, n<m, If[PrimeQ[10^n-41], Print[n]]; n++ ]`
	PROG	`(PARI) is(n)=ispseudoprime(10^n-41) \\ Charles R Greathouse IV, Jun 13 2017`
	CROSSREFS	`Cf. A108330, A108328.` `Sequence in context: A276154 A328770 A138626 * A189515 A190344 A287000` `Adjacent sequences: A178403 A178404 A178405 * A178407 A178408 A178409`
	KEYWORD	`more,nonn`
	AUTHOR	`Robert Price, Dec 21 2010`
	EXTENSIONS	`a(20)=43873 from Robert Price, Apr 25 2011` `a(21) from Kamada data by Robert Price, Apr 12 2015`
	STATUS	`approved`

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Last modified December 6 03:51 EST 2023. Contains 367595 sequences. (Running on oeis4.)