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 A374179 #14 Jul 10 2024 15:03:17 %S A374179 2,11,47,139,157,191,1151,1531,3067,7159,20479,36857,49139,98299, %T A374179 360439,917503,1310719,786431,6291449,5242877,20971507,58720253, %U A374179 83886053,201326557,335544301,402653171,3489660919,1879048183,5368709117,25769803751,21474836479,77309411323 %N A374179 a(n) is the least prime p such that the binary expansions of p and of the next prime q > p differ at exactly n positions, and p and q have the same binary length. %e A374179 a(n): 2 11 47 139 157 %e A374179 np 3 13 53 149 163 %e A374179 [1 0] [1 0 1 1] [1 0 1 1 1 1] [1 0 0 0 1 0 1 1] [1 0 0 1 1 1 0 1] %e A374179 [1 1] [1 1 0 1] [1 1 0 1 0 1] [1 0 0 1 0 1 0 1] [1 0 1 0 0 0 1 1] %e A374179 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ %e A374179 n: 1 2 3 4 5 %o A374179 (Python) %o A374179 from sympy import nextprime %o A374179 def A374179(n): %o A374179 p, pb = 2, 2 %o A374179 while (q:=nextprime(p)): %o A374179 if pb==(qb:=q.bit_length()) and (p^q).bit_count() == n: %o A374179 return p %o A374179 p, pb = q, qb # _Chai Wah Wu_, Jul 10 2024 %Y A374179 Cf. A000120, A000788, A007088, A061712, A205510, A374178. %K A374179 nonn,base %O A374179 1,1 %A A374179 _Hugo Pfoertner_, Jul 09 2024