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.

A296107 Twin prime pairs both of which have the same number of prime digits.

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%I A296107 #9 Dec 05 2017 17:24:22
%S A296107 3,5,5,7,29,31,809,811,1229,1231,1289,1291,2129,2131,2309,2311,2729,
%T A296107 2731,2789,2791,2999,3001,3299,3301,3329,3331,3389,3391,3929,3931,
%U A296107 4229,4231,5009,5011,5099,5101,6089,6091,6299,6301,6689,6691,7589,7591,8009,8011
%N A296107 Twin prime pairs both of which have the same number of prime digits.
%C A296107 This was essentially the original definition of A158284 but the given terms to that sequence did not match this definition.
%H A296107 Charles R Greathouse IV, <a href="/A296107/b296107.txt">Table of n, a(n) for n = 1..10000</a>
%e A296107 3929 and 3931 are twin primes and both have two prime digits.
%t A296107 Select[Partition[Prime[Range[2000]],2,1],#[[2]]-#[[1]]==2 && Count[ IntegerDigits[#[[1]]],_?PrimeQ]==Count[IntegerDigits[#[[2]]], _?PrimeQ]&]//Flatten
%o A296107 (PARI) ct(n)=my(d=digits(n)); sum(i=1,#d, isprime(d[i]))
%o A296107 do(lim)=my(v=List(),p=3); forprime(q=5,lim+2, if(q-p==2 && ct(p)==ct(q), listput(v,p); listput(v,q)); p=q); Vec(v) \\ _Charles R Greathouse IV_, Dec 05 2017
%Y A296107 Cf. A158284.
%K A296107 nonn,base
%O A296107 1,1
%A A296107 _Harvey P. Dale_, Dec 04 2017