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 A023340 #21 Sep 08 2022 08:44:47 %S A023340 18257,19541,22063,48383,73037,73133,78173,88261,93811,101051,104537, %T A023340 152377,153941,162343,168043,175523,204251,211681,238463,287341, %U A023340 375253,386713,423961,659513,672181,676103,688027,741283,759491,770951,786673 %N A023340 Primes that remain prime through 5 iterations of function f(x) = 4x + 9. %C A023340 Primes p such that 4*p+9, 16*p+45, 64*p+189, 256*p+765 and 1024*p+3069 are also primes. - _Vincenzo Librandi_, Aug 05 2010 %H A023340 John Cerkan, <a href="/A023340/b023340.txt">Table of n, a(n) for n = 1..10000</a> %o A023340 (Magma) [n: n in [1..10000000] | IsPrime(n) and IsPrime(4*n+9) and IsPrime(16*n+45) and IsPrime(64*n+189) and IsPrime(256*n+765) and IsPrime(1024*n+3069)] // _Vincenzo Librandi_, Aug 05 2010 %o A023340 (PARI) is(n)=isprime(n) && isprime(4*n+9) && isprime(16*n+45) && isprime(64*n+189) && isprime(256*n+765) && isprime(1024*n+3069) \\ _Charles R Greathouse IV_, Oct 11 2016 %Y A023340 Subsequence of A023216, A023251, A023282, A023312, and A111199. %K A023340 nonn %O A023340 1,1 %A A023340 _David W. Wilson_