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 A049095 #26 May 31 2024 05:48:38 %S A049095 0,1,2,4,5,6,7,8,11,12,13,14,16,17,18,19,20,22,23,24,25,26,28,29,31, %T A049095 32,34,35,36,37,38,40,41,42,43,44,46,47,48,49,52,53,54,56,58,59,60,61, %U A049095 62,64,65,66,67,71,72,73,74,76,77,79,80,82,83,84,85,86,88,89,91,92,94,95 %N A049095 Numbers k such that 2^k + 1 is squarefree. %H A049095 Amiram Eldar, <a href="/A049095/b049095.txt">Table of n, a(n) for n = 1..10000</a> (calculated from the b-file at A049096) %e A049095 8 is in the sequence because 2^8 + 1 = 257 is prime, hence it is squarefree. %e A049095 9 is not in the sequence because 2^9 + 1 = 513 is divisible by a square, 9. %t A049095 Select[Range[0,95], SquareFreeQ[2^# + 1] &] (* _Michael De Vlieger_, Jun 29 2017 *) %o A049095 (PARI) isok(n) = issquarefree(2^n + 1); \\ _Michel Marcus_, Dec 18 2013 %Y A049095 Complement of A049096. %K A049095 nonn %O A049095 1,3 %A A049095 _Labos Elemer_ %E A049095 0 prepended by _Jianing Song_, May 28 2024