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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A154531 Primes that are a concatenation of consecutive primes in two ways. 2

%I

%S 199211,211199,233239,239233,257263,263257,353359,359353,523541,

%T 541523,653659,659653,971977,977971,19731979,19791973,23332339,

%U 23392333,32593271,32713259,36373643,36433637,37613767,37673761,42834289,42894283,49934999,49994993

%N Primes that are a concatenation of consecutive primes in two ways.

%H Harvey P. Dale, <a href="/A154531/b154531.txt">Table of n, a(n) for n = 1..1000</a>

%e 233 and 239 consecutive primes, 233239 and 239233 are both primes.

%t ccp2[{a_,b_}]:=Module[{c=a*10^IntegerLength[b]+b,d=b*10^IntegerLength[a]+ a}, If[ AllTrue[ {c,d}, PrimeQ],{c,d},{}]]; ccp2/@Partition[Prime[ Range[ 1000]],2,1]//Flatten (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Feb 20 2017 *)

%Y Cf. A133986, A154530.

%K nonn,base

%O 1,1

%A _Pierre CAMI_, Jan 11 2009

%E Corrected by _Harvey P. Dale_, Feb 20 2017

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.

Last modified July 27 13:36 EDT 2021. Contains 346306 sequences. (Running on oeis4.)