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.
%I A046704 #46 Sep 08 2022 08:44:56 %S A046704 2,3,5,7,11,23,29,41,43,47,61,67,83,89,101,113,131,137,139,151,157, %T A046704 173,179,191,193,197,199,223,227,229,241,263,269,281,283,311,313,317, %U A046704 331,337,353,359,373,379,397,401,409,421,443,449,461,463,467,487,557,571,577,593 %N A046704 Additive primes: sum of digits is a prime. %C A046704 Sum_{a(n) < x} 1/a(n) is asymptotic to (3/2)*log(log(log(x))) as x -> infinity; see Harman (2012). Thus the sequence is infinite. - _Jonathan Sondow_, Jun 07 2012 %C A046704 Harman 2012 also shows, under a conjecture about primes in short intervals, that there are 3/2 * x/(log x log log x) terms up to x. - _Charles R Greathouse IV_, Nov 17 2014 %H A046704 Reinhard Zumkeller, <a href="/A046704/b046704.txt">Table of n, a(n) for n = 1..10000</a> %H A046704 Glyn Harman, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL15/Harman/harman2.html">Counting primes whose sum of digits is prime</a>, J. Integer Seq., 15 (2012), Article 12.2.2. %H A046704 Glyn Harman, <a href="http://dx.doi.org/10.1112/blms/bds034">Primes whose sum of digits is prime and metric number theory</a>, Bull. Lond. Math. Soc. 44:5 (2012), pp. 1042-1049. %e A046704 The digit sums of 11 and 13 are 1+1=2 and 1+3=4. Since 2 is prime and 4 is not, 11 is a member and 13 is not. - _Jonathan Sondow_, Jun 07 2012 %p A046704 select(n -> isprime(n) and isprime(convert(convert(n,base,10),`+`)), [2,seq(2*i+1,i=1..1000)]); # _Robert Israel_, Nov 17 2014 %t A046704 Select[Prime[Range[100000]], PrimeQ[Apply[Plus, IntegerDigits[ # ]]]&] %o A046704 (PARI) isA046704(n)={local(s,m);s=0;m=n;while(m>0,s=s+m%10;m=floor(m/10));isprime(n) & isprime(s)} \\ _Michael B. Porter_, Oct 18 2009 %o A046704 (PARI) is(n)=isprime(n) && isprime(sumdigits(n)) \\ _Charles R Greathouse IV_, Dec 26 2013 %o A046704 (Magma) [ p: p in PrimesUpTo(600) | IsPrime(&+Intseq(p)) ]; // _Bruno Berselli_, Jul 08 2011 %o A046704 (Haskell) %o A046704 a046704 n = a046704_list !! (n-1) %o A046704 a046704_list = filter ((== 1) . a010051 . a007953) a000040_list %o A046704 -- _Reinhard Zumkeller_, Nov 13 2011 %Y A046704 Indices of additive primes are in A075177. %Y A046704 Cf. A046703, A119450 = Primes with odd digit sum, A081092 = Primes with prime binary digit sum, A104213 = Primes with nonprime digit sum. %Y A046704 Cf. A007953, A010051; intersection of A028834 and A000040. %K A046704 base,nonn %O A046704 1,1 %A A046704 _Felice Russo_