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 A195351 #17 Aug 18 2025 00:09:26 %S A195351 0,25,27,45,49,97,99,113,139,176,186,208,216,227,232,259,298,309,332, %T A195351 358,362,364,387,490,631,659,662,676,698,705,718,726,737,747,781,849, %U A195351 860,862,901,913,918,936,958,965,966,992,998 %N A195351 Numbers k such that there are no primes in the range [2^k-k, 2^k+k]. %C A195351 If a(n) is prime then it is not in A000043. - _Alonso del Arte_, Oct 07 2011 %F A195351 A192454(a(n))=0. %t A195351 Select[Range[0, 49], PrimePi[2^# - # - 1] == PrimePi[2^# + #] &] (* _Alonso del Arte_, Oct 07 2011 *) %Y A195351 Cf. A192454. %K A195351 nonn %O A195351 1,2 %A A195351 _Juri-Stepan Gerasimov_, Sep 16 2011