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A167847 Straight-line primes. 3

%I

%S 11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,4567,

%T 76543,23456789,1111111111111111111,11111111111111111111111

%N Straight-line primes.

%C Prime numbers with 2 digits together with the primes whose digits are in arithmetic progression. The structure of digits represent a straight line.

%C Note that in the graphic representation the points are connected by imaginary line segments (see also A135643).

%C Note that all primes with two are straight-line primes but there are no members of this sequence with three digits.

%C No further terms between 23456789 and 115507867=prime(6600000). [From _R. J. Mathar_, Dec 04 2009]

%C 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

%e The number 4567 is straight-line prime:

%e . . . .

%e . . . .

%e . . . 7

%e . . 6 .

%e . 5 . .

%e 4 . . .

%e . . . .

%e . . . .

%e . . . .

%e . . . .

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

%K base,nonn

%O 1,1

%A _Omar E. Pol_, Nov 14 2009

%E 2 more terms from _R. J. Mathar_, Dec 04 2009

%E a(25)-a(26) from _Jens Kruse Andersen_, Jul 21 2014

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Last modified July 19 03:54 EDT 2019. Contains 325144 sequences. (Running on oeis4.)