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A068645 Primes in which a string of 3's is sandwiched between two 1's. 8
11, 131, 13331, 1333331, 13333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333331 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(5) consists of 93 and a(6) consists of 159 3's sandwiched between two 1's. - Sascha Kurz, Mar 26 2002

LINKS

Table of n, a(n) for n=1..5.

Patrick De Geest, PDP Reference Table - 131.

Makoto Kamada, Prime numbers of the form 133...331.

Index entries for primes involving repunits.

CROSSREFS

Cf. A056244, A082697.

Sequence in context: A261689 A101334 A222872 * A097258 A044041 A158536

Adjacent sequences:  A068642 A068643 A068644 * A068646 A068647 A068648

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Feb 28 2002

EXTENSIONS

More terms from Sascha Kurz, Mar 26 2002

Edited by Ray Chandler, Nov 04 2014

STATUS

approved

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Last modified May 21 18:58 EDT 2019. Contains 323444 sequences. (Running on oeis4.)