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A049054 Numbers n such that 10^n + 3 is prime. 27
1, 2, 5, 6, 11, 17, 18, 39, 56, 101, 105, 107, 123, 413, 426, 2607, 7668, 10470, 11021, 17753, 26927, 60776, 98288, 300476 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A102006 is another version of the same sequence. - N. J. A. Sloane, Jan 28 2010.

Verified existing 21 terms. If another term exists, it is > 39456. - Robert Price, Aug 16 2010

LINKS

Table of n, a(n) for n=1..24.

Makoto Kamada, Prime numbers of the form 100...003.

Henri & Renaud Lifchitz, PRP Records.

Sabin Tabirca and Kieran Reynolds, Lacunary Prime Numbers.

FORMULA

a(n) = A102006(n) + 1.

EXAMPLE

5 is a member since 10^5 + 3 = 100003 is a prime.

6 is a member since 10^6 + 3 = 1000003 is a prime.

MATHEMATICA

Do[ If[ PrimeQ[ 10^n + 3], Print[n]], {n, 0, 18000}] (* Robert G. Wilson v Jun 15 2002 *)

PROG

(PARI) is(n)=isprime(10^n + 3) \\ Charles R Greathouse IV, Apr 28 2015

CROSSREFS

Cf. A102006, A159352.

Sequence in context: A180323 A103035 A088273 * A135476 A255310 A051217

Adjacent sequences:  A049051 A049052 A049053 * A049055 A049056 A049057

KEYWORD

hard,more,nonn

AUTHOR

G. L. Honaker, Jr.

EXTENSIONS

More terms from Robert G. Wilson v, Jun 15 2002

a(16) from Ray Chandler, Oct 09 2003

a(17)-a(20) from Robert G. Wilson v, Jan 18 2005

a(21)=26927 from Jason Earls (zevi_35711(AT)yahoo.com), Jan 01 2008

a(22)=60776 from Robert Price, Jan 09 2011

a(23)=98288 from Robert Price, Mar 03 2011

a(24)=300476 from Edward A. Trice, Oct 21 2012

STATUS

approved

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Last modified September 26 05:09 EDT 2017. Contains 292502 sequences.