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A087395 Primes in which the frequency of every digit is the same and is at least 2.

%I A087395 #18 Nov 19 2022 20:18:37
%S A087395 11,100313,107071,110909,114343,115757,116969,117373,117979,118787,
%T A087395 119797,121727,127217,127271,131939,133717,133919,134341,136163,
%U A087395 136361,137713,140401,141499,142421,143413,145451,149419,149491,155717,157571
%N A087395 Primes in which the frequency of every digit is the same and is at least 2.
%C A087395 If d is prime, the only terms with d digits are repunit primes (A004022). - _Robert Israel_, Nov 18 2022
%H A087395 Michael S. Branicky, <a href="/A087395/b087395.txt">Table of n, a(n) for n = 1..10000</a>
%H A087395 Michael S. Branicky, <a href="/A087395/a087395.py.txt">Python program</a>
%e A087395 100313 is a term in which each of the digits 1, 3 and 0 occurs with frequency 2.
%p A087395 filter:= proc(n) local L,d,S;
%p A087395   if not isprime(n) then return false fi;
%p A087395   L:= convert(n,base,10);
%p A087395   S:={seq(numboccur(d,L),d=convert(L,set))};
%p A087395   nops(S) = 1 and S[1]>=2
%p A087395 end proc:
%p A087395 select(filter, [seq(i,i=11 .. 200000, 2)]); # _Robert Israel_, Nov 18 2022
%t A087395 fpQ[n_]:=Module[{dc=Union[Cases[DigitCount[n],Except[0]]]}, First[dc]>1 &&Length[dc]==1]; Select[Prime[Range[14500]],fpQ] (* _Harvey P. Dale_, Apr 22 2011 *)
%o A087395 (Python) # see linked program for a faster version
%o A087395 from sympy import isprime
%o A087395 from collections import Counter
%o A087395 from itertools import count, islice
%o A087395 def ok(n):
%o A087395     cv = Counter(str(n)).values()
%o A087395     return min(cv) >= 2 and len(set(cv)) == 1 and isprime(n)
%o A087395 def agen():
%o A087395     evdigs = (k for d in count(2, 2) for k in range(10**(d-1)+1, 10**d, 2))
%o A087395     yield from (k for k in evdigs if ok(k))
%o A087395 print(list(islice(agen(), 30))) # _Michael S. Branicky_, Nov 18 2022
%Y A087395 Contains A004022.
%K A087395 base,nonn
%O A087395 1,1
%A A087395 _Amarnath Murthy_, Sep 10 2003
%E A087395 Corrected and extended by _David Wasserman_, May 31 2005