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 A023350 #25 Jul 21 2025 08:57:10 %S A023350 25589,220469,225629,286619,783269,1215629,1407389,1542029,1642919, %T A023350 2329469,2776979,3104159,4082759,4229129,5405999,5905619,6548849, %U A023350 6862859,7681409,7904669,8623799,8971049,9599309,9658469,9725039,11420579 %N A023350 Primes that remain prime through 5 iterations of function f(x) = 8x + 7. %C A023350 Primes p such that 8*p+7, 64*p+63, 512*p+511, 4096*p+4095 and 32768*p+32767 are also primes. - _Vincenzo Librandi_, Aug 05 2010 %H A023350 John Cerkan, <a href="/A023350/b023350.txt">Table of n, a(n) for n = 1..10000</a> %F A023350 a(n) == 29 (mod 30). - _John Cerkan_, Nov 08 2016 %t A023350 i5Q[p_]:=AllTrue[Rest[NestList[8#+7&,p,5]],PrimeQ]; Select[Prime[Range[760000]],i5Q] (* _Harvey P. Dale_, Jul 05 2025 *) %o A023350 (Magma) [n: n in [1..19000000] | IsPrime(n) and IsPrime(8*n+7) and IsPrime(64*n+63) and IsPrime(512*n+511) and IsPrime(4096*n+4095) and IsPrime(32768*n+32767)]; // _Vincenzo Librandi_, Aug 05 2010 %Y A023350 Subsequence of A023231, A023263, A023294, A023322, and A139487. %K A023350 nonn %O A023350 1,1 %A A023350 _David W. Wilson_