cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A344628 Primes p such that exactly four numbers among all circular permutations of the digits of p are prime.

Original entry on oeis.org

1193, 1931, 3119, 3779, 7793, 7937, 9311, 9377, 11393, 11701, 11717, 11743, 13177, 13931, 13997, 16993, 17011, 17117, 17431, 17539, 17713, 19717, 19997, 21737, 23339, 23773, 30197, 31139, 31699, 31771, 32377, 33923, 37217, 38197, 39233, 39499, 39799, 39971
Offset: 1

Views

Author

Felix Fröhlich, May 25 2021

Keywords

Crossrefs

Cf. A270083. Row 4 of A317716.
Cf. primes where exactly k numbers among all circular permutations of digits are prime: A068654 (k=1), A344626 (k=2), A344627 (k=3), A344629 (k=5), A344630 (k=6), A344631 (k=7), A344632 (k=8).

Programs

  • Mathematica
    Select[Prime[Range[4500]],Count[FromDigits/@Table[RotateRight[IntegerDigits[#],d],{d,IntegerLength[ #]}],?PrimeQ]==4&] (* _Harvey P. Dale, Aug 31 2024 *)
  • 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
    eva(n) = subst(Pol(n), x, 10)
    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==4, 1, 0)
    forprime(p=1, 1e3, if(is(p), print1(p, ", ")))