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!)
A180440 Primes p such that p+reverse(p) is twice a prime. 1
2, 3, 5, 7, 11, 101, 131, 151, 181, 191, 313, 353, 373, 383, 571, 599, 727, 757, 787, 797, 919, 929, 10037, 10093, 10133, 10253, 10301, 10313, 10321, 10333, 10357, 10457, 10501, 10601, 10613, 10753, 10781, 10853, 10861, 10993, 11003, 11027, 11083 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Except for p=2, the sum of a prime and its reversed is even, therefore such a sum, divided by 2, is an integer.

All palindromic primes belong to this sequence since reverse(p)=p.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..5000

EXAMPLE

a(15)=571 since 571+reverse(571)=571+175=746 and 746/2=373 is a prime

MATHEMATICA

Select[Prime[Range[1500]], PrimeQ[(#+IntegerReverse[#])/2]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 22 2019 *)

CROSSREFS

Cf. A000040, A002385

Sequence in context: A052480 A234912 A083137 * A077652 A002385 A069217

Adjacent sequences:  A180437 A180438 A180439 * A180441 A180442 A180443

KEYWORD

nonn,base

AUTHOR

Carmine Suriano, Sep 05 2010

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 September 22 22:24 EDT 2020. Contains 337291 sequences. (Running on oeis4.)