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A167847 Straight-line primes. 3
11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 4567, 76543, 23456789, 1111111111111111111, 11111111111111111111111 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Prime numbers with 2 digits together with the primes whose digits are in arithmetic progression. The structure of digits represents a straight line.
Note that in the graphic representation the points are connected by imaginary line segments (see also A135643).
Note that all two-digit primes are straight-line primes but this sequence has no three-digit terms.
No further terms between 23456789 and 115507867=prime(6600000). - R. J. Mathar, Dec 04 2009
All terms after 23456789 are repunit primes (A004022) with number of digits: 19, 23, 317, 1031, 49081, 86453, 109297, 270343, ... (A004023). - Jens Kruse Andersen, Jul 21 2014
LINKS
EXAMPLE
The number 4567 is straight-line prime:
. . . .
. . . .
. . . 7
. . 6 .
. 5 . .
4 . . .
. . . .
. . . .
. . . .
. . . .
CROSSREFS
Sequence in context: A108871 A347819 A268031 * A135779 A135778 A078875
KEYWORD
base,nonn
AUTHOR
Omar E. Pol, Nov 14 2009
EXTENSIONS
2 more terms from R. J. Mathar, Dec 04 2009
a(25)-a(26) from Jens Kruse Andersen, Jul 21 2014
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)