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!)
A270083 Near-miss circular primes: Primes p where all but one of the numbers obtained by cyclically permuting the digits of p are prime. 14

%I #33 Mar 03 2024 08:35:34

%S 19,23,29,41,43,47,53,59,61,67,83,89,101,103,107,127,149,157,163,173,

%T 181,191,271,277,307,313,317,331,359,367,379,397,419,479,491,571,577,

%U 593,617,631,673,701,709,727,739,757,761,787,797,811,839,877,907,911

%N Near-miss circular primes: Primes p where all but one of the numbers obtained by cyclically permuting the digits of p are prime.

%C Prime p is a term of the sequence iff A262988(p) = A055642(p) - 1.

%C If a(512) exists, it is larger than 10^16. - _Giovanni Resta_, Apr 27 2017

%C If one of the digits is even or 5, the miss occurs when that digit is permuted to the ones place. Avoiding that simple obstruction, this sequence intersected with A091633 is 19, 173, 191, 313, 317, 331, 379, 397, 739, 797, 911, 937, 977, 1319, 1777, 1913, 1979, 1993, 3191, 3373, 3719, 3733, 3793, ... . Is this an infinite subsequence? - _Danny Rorabaugh_, May 15 2017

%H Felix Fröhlich and Giovanni Resta, <a href="/A270083/b270083.txt">Table of n, a(n) for n = 1..511</a> (first 487 terms from Felix Fröhlich)

%t NearCircPrmsUpTo10powerK[k_]:= Union @ Flatten[ Table[ParallelMap[If[(Count[FromDigits /@ NestList[RotateLeft, IntegerDigits[#], IntegerLength[#]-1], _?PrimeQ] == IntegerLength[#]-1), #, Nothing] &, Select[FromDigits /@ Tuples[Range[0, 9], n], PrimeQ]], {n, k}], 1]; NearCircPrmsUpTo10powerK[7] (* _Mikk Heidemaa_, Apr 26 2017 *)

%o (PARI) rot(n) = if(#Str(n)==1, v=vector(1), v=vector(#n-1)); for(i=2, #n, v[i-1]=n[i]); u=vector(#n); for(i=1, #n, u[i]=n[i]); v=concat(v, u[1]); v

%o eva(n) = subst(Pol(n), x, 10)

%o is(n) = my(r=rot(digits(n)), i=0); while(r!=digits(n), if(ispseudoprime(eva(r)), i++); r=rot(r)); if(ispseudoprime(eva(r)), i++); if(n==1 || n==11, return(0)); if(i==#Str(n)-1, 1, 0)

%o forprime(p=1, 1e3, if(is(p), print1(p, ", ")))

%Y Cf. A045978, A068652, A262988.

%K nonn,base

%O 1,1

%A _Felix Fröhlich_, Mar 10 2016

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 April 19 17:51 EDT 2024. Contains 371797 sequences. (Running on oeis4.)