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 A109981 #8 Jul 13 2013 12:03:21 %S A109981 11,23,29,41,43,47,61,67,83,89,101,113,131,137,139,151,157,173,179, %T A109981 191,193,197,199,223,227,229,241,263,269,281,283,311,313,317,331,337, %U A109981 353,359,373,379,397,401,409,421,443,449,461,463,467,487,557,571,577,593 %N A109981 Primes such that both the sum of digits and the number of digits are primes. %C A109981 Cf. A046704 Additive primes: sum of digits is a prime, A088136 Primes such that sum of first and last digits is prime. %H A109981 Reinhard Zumkeller, <a href="/A109981/b109981.txt">Table of n, a(n) for n = 1..10000</a> %H A109981 G. Harman, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL15/Harman/harman2.pdf">Counting Primes whose Sum of Digits is Prime</a>, J. Integer Seq., 15 (2012), Article 12.2.2. %e A109981 a(86) = 10037 because both the sum (=11) and number (=5) of digits are primes. %t A109981 Select[Prime[Range[200]], PrimeQ[Length[IntegerDigits[ # ]]]&&PrimeQ[Plus@@IntegerDigits[ # ]]&] %o A109981 (Haskell) %o A109981 a109981 n = a109981_list !! (n-1) %o A109981 a109981_list = filter ((== 1) . a010051' . a055642) a046704_list %o A109981 -- _Reinhard Zumkeller_, Nov 16 2012 %Y A109981 Cf. A046704, A088136. %Y A109981 Cf. A010051, A055642. %K A109981 base,nonn %O A109981 1,1 %A A109981 _Zak Seidov_, Jul 06 2005