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 A023278 #22 Sep 08 2022 08:44:47 %S A023278 23,683,1663,2753,3203,6073,6323,7523,8243,9293,9613,15173,19913, %T A023278 21023,21683,25183,26633,29663,34613,34703,39293,41953,43283,45533, %U A023278 52813,59393,62473,65053,66763,71713,71993,81533,81953,84523,87833,103843,104183 %N A023278 Primes that remain prime through 3 iterations of function f(x) = 3x + 4. %C A023278 Primes p such that 3*p+4, 9*p+16 and 27*p+52 are also primes. - _Vincenzo Librandi_, Aug 04 2010 %H A023278 John Cerkan, <a href="/A023278/b023278.txt">Table of n, a(n) for n = 1..10000</a> %F A023278 a(n) == 3 (mod 10). - _John Cerkan_, Sep 16 2016 %t A023278 Select[Prime@ Range[10^4], Times @@ Boole@ PrimeQ@ Rest@ NestList[3 # + 4 &, #, 3] > 0 &] (* _Michael De Vlieger_, Sep 19 2016 *) %o A023278 (Magma) [n: n in [1..150000] | IsPrime(n) and IsPrime(3*n+4) and IsPrime(9*n+16) and IsPrime(27*n+52)] // _Vincenzo Librandi_, Aug 04 2010 %o A023278 (PARI) is(n)=isprime(n) && isprime(3*n+4) && isprime(9*n+16) && isprime(27*n+52) \\ _Charles R Greathouse IV_, Sep 20 2016 %Y A023278 Subsequence of A023209, A023247, and of A034936. %K A023278 nonn %O A023278 1,1 %A A023278 _David W. Wilson_