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 A073718 #14 Aug 11 2020 09:54:55
%S A073718 16,64,256,512,1024,4096,16384,32768,65536,262144,1048576,2097152,
%T A073718 4194304,16777216,33554432,67108864,134217728,268435456,1073741824,
%U A073718 4294967296,8589934592,17179869184,34359738368,68719476736
%N A073718 Powers of 2 with composite exponents.
%H A073718 <a href="/index/Di#divseq">Index to divisibility sequences</a>
%F A073718 a(n) = 2^A002808(n) = A000079(A002808(n)).
%F A073718 Sum_{n>=1} 1/a(n) = A275306. - _Amiram Eldar_, Aug 11 2020
%t A073718 Table[2^FixedPoint[n+PrimePi[ # ]+1&, n], {n, 1, 30}]
%o A073718 (PARI) for(n=4,100,if(!isprime(n),print1(2^n", "))) \\ _Charles R Greathouse IV_, Apr 09 2012
%Y A073718 Cf. A000079, A002808, A275306.
%K A073718 easy,nonn
%O A073718 1,1
%A A073718 _Labos Elemer_, Aug 05 2002