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 A165439 #18 Sep 03 2025 00:52:02 %S A165439 2,5,7,11,13,17,19,23,31,37,41,43,53,59,61,67,71,73,89,101,103,107, %T A165439 109,113,127,131,139,149,151,157,163,167,179,181,193,197,199,211,223, %U A165439 229,233,239,241,251,257,269,271,283,293,307,311,313,331,337,347,359,373 %N A165439 Primes p such that 3+2*(sum of digits of p) is also a prime. %H A165439 Bruno Berselli, <a href="/A165439/b165439.txt">Table of n, a(n) for n = 1..1000</a> %e A165439 331 is in the sequence because 3+3+1=7 and 2*7+3=17 is prime. %t A165439 Select[Prime[Range[200]],PrimeQ[2 Total[IntegerDigits[#]]+3]&] (* _Harvey P. Dale_, Jul 14 2011 *) %o A165439 (Magma) [ p: p in PrimesUpTo(400) | IsPrime(q) where q is 3+2*(&+Intseq(p))]; // _Bruno Berselli_, Jul 15 2011 %Y A165439 Cf. A165440, A007605. %K A165439 nonn,base,changed %O A165439 1,1 %A A165439 _Vincenzo Librandi_, Sep 19 2009 %E A165439 Keyword:base added by _R. J. Mathar_, Oct 12 2009