login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A163681 Smaller prime p in Ormiston pairs (p, q) with q - p = 72. 1

%I #9 Sep 08 2022 08:45:47

%S 1290719,1477219,1802419,2520697,2902519,3327419,3391697,3498119,

%T 4596419,4641919,4709519,5521819,5835619,6091031,6267419,6642919,

%U 6943919,7118519,7480519,8241019,8630519,8934319,8946919,9859697

%N Smaller prime p in Ormiston pairs (p, q) with q - p = 72.

%C An Ormiston pair (or rearrangement prime pair) is a pair of consecutive primes that use the same digits in a different order.

%H Jens Kruse Andersen, <a href="http://primerecords.dk/ormiston_tuples.htm">Ormiston Tuples</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RearrangementPrimePair.html">Rearrangement Prime Pair</a>

%e (1802419, 1802491) is an Ormiston pair with gap 72, so 1802419 is in the sequence.

%t Transpose[Select[Select[Partition[Prime[Range[800000]],2,1],Last[#]-First[#]==72&],Sort[IntegerDigits[First[#]]]==Sort[IntegerDigits[Last[#]]]&]][[1]] (* _Harvey P. Dale_, Feb 14 2011 *)

%o (Magma) [ p: p in PrimesUpTo(10000000) | q-p eq 72 and a eq b where a is Sort(Intseq(p)) where b is Sort(Intseq(q)) where q is NextPrime(p) ];

%Y Subsequence of A069567.

%Y Cf. A072274, A163863.

%K nonn,base

%O 1,1

%A _Klaus Brockhaus_, Aug 03 2009

%E Keyword base added by _Klaus Brockhaus_, Sep 18 2009

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 01:36 EDT 2024. Contains 371264 sequences. (Running on oeis4.)