login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A141263 Lesser of a prime/emirp pair. 2
2, 3, 5, 7, 11, 13, 17, 37, 79, 101, 107, 113, 131, 149, 151, 157, 167, 179, 181, 191, 199, 313, 337, 347, 353, 359, 373, 383, 389, 709, 727, 739, 757, 769, 787, 797, 919, 929, 1009, 1021, 1031, 1033, 1061, 1069, 1091, 1097, 1103, 1109, 1151, 1153, 1181 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

From the set of numbers that are both prime and emirp choose the smaller one of each pair (whenever more than one decimal digit is involved).

A002385 is subset of this sequence.

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..1000

EXAMPLE

31 does not appear since we have already seen 13.

MATHEMATICA

pp[n_] := Module[{nr=FromDigits[Reverse[IntegerDigits[n]]]}, If[PrimeQ[nr], Sort[{n, nr}]]]; Transpose[Rest[Union[pp/@Prime[Range[200]]]]][[1]] (* Harvey P. Dale, Dec 18 2010 *)

PROG

(Python)

from gmpy2 import next_prime, is_prime

A141263_list, p = [], 1

for _ in range(1, 10**4):

....p = next_prime(p)

....ps = int(str(p)[::-1])

....if p <= ps and is_prime(ps):

........A141263_list.append(int(p)) # Chai Wah Wu, Jun 11 2015

CROSSREFS

Cf. A002385, A007500.

Sequence in context: A118725 A117835 A120639 * A016114 A263499 A258706

Adjacent sequences:  A141260 A141261 A141262 * A141264 A141265 A141266

KEYWORD

nonn,base

AUTHOR

Artur Jasinski, Jun 20 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 13 05:41 EDT 2020. Contains 336442 sequences. (Running on oeis4.)