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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

Table of n, a(n) for n=1..26.

EXAMPLE

The number 4567 is straight-line prime:

. . . .

. . . .

. . . 7

. . 6 .

. 5 . .

4 . . .

. . . .

. . . .

. . . .

. . . .

CROSSREFS

Cf. A000040, A004022, A004023, A134811, A134951, A134971, A135643, A167841, A167842, A167843, A167844, A167845, A167846, A167853.

Sequence in context: A108871 A347819 A268031 * A135779 A135778 A078875

Adjacent sequences: A167844 A167845 A167846 * A167848 A167849 A167850

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 December 5 19:04 EST 2022. Contains 358588 sequences. (Running on oeis4.)