A344631 Primes p such that exactly seven numbers among all circular permutations of the digits of p are prime.

17773937, 39371777, 71777393, 73937177, 77393717, 77739371, 93717773, 101717933, 101793137, 111766999, 111897767, 113379997, 113719261, 113773021, 113913133, 117669991, 118977671, 119307977, 119937137, 123975113, 131239751, 131331139, 131473193, 133113913

Offset

1,1

Links

Table of n, a(n) for n=1..24.

Prog

(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==7, 1, 0)
forprime(p=1, 1e3, if(is(p), print1(p, ", ")))

Crossrefs

Cf. A270083. Row 7 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), A344628 (k=4), A344629 (k=5), A344630 (k=6), A344632 (k=8).

Sequence in context: A032749 A235848 A250981 * A159192 A154875 A015353

Adjacent sequences: A344628 A344629 A344630 * A344632 A344633 A344634

Keyword

nonn,base

Author

Felix Fröhlich, May 25 2021

Status

approved