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 A053159 #9 Oct 30 2022 18:19:59 %S A053159 1,3,7,10,20,31,40,80,127,160,320,322,640,644,1280,1288,2560,2576, %T A053159 5120,5152,8191,10240,10304,20480,20608,40960,41216,81920,82432, %U A053159 131071,163840,164864,327680,329728,333634,524287,655360,659456,667268,1310720,1318912 %N A053159 Numbers n such that n+cototient(n) is a power of 2. %C A053159 See especially A053579 and also A053576, A053577. %H A053159 Donovan Johnson, <a href="/A053159/b053159.txt">Table of n, a(n) for n = 1..100</a> %F A053159 a(n)+A051953(n) = 2*a(n)-A000010(n) = 2^w for some w. %e A053159 Mersenne primes are a proper subset of this sequence: A(M)=2M-M+1=M+1=2^p %o A053159 (PARI) print(1); for(n=3, 10^9, if(omega(2*n-eulerphi(n))==1, print(n))) /* _Donovan Johnson_, Apr 04 2013 */ %Y A053159 Cf. A000043, A000668, A001348. %K A053159 nonn %O A053159 1,2 %A A053159 _Labos Elemer_, Feb 29 2000 %E A053159 More terms from _Reiner Martin_, Dec 24 2001