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 A004676 #37 Oct 26 2023 01:01:16 %S A004676 10,11,101,111,1011,1101,10001,10011,10111,11101,11111,100101,101001, %T A004676 101011,101111,110101,111011,111101,1000011,1000111,1001001,1001111, %U A004676 1010011,1011001,1100001,1100101,1100111,1101011,1101101,1110001,1111111,10000011,10001001 %N A004676 Primes written in base 2. %C A004676 The only primes of binary weight 2 are the Fermat primes (only five are known: 11, 101, 10001, 100000001, 10000000000000001); the repunits base 2 are the Mersenne primes. - _Daniel Forgues_, Nov 07 2011 %D A004676 J.-P. Allouche and J. Shallit, Automatic Sequences, Cambridge Univ. Press, 2003, p. 3. %H A004676 T. D. Noe, <a href="/A004676/b004676.txt">Table of n, a(n) for n = 1..1000</a> %H A004676 Chris Caldwell, The prime pages, <a href="http://www.utm.edu/research/primes/lists/small/1000.txt">The first 1000 primes</a>. %F A004676 a(n) = A007088(A000040(n)). - _R. J. Mathar_, Jun 03 2011 %t A004676 FromDigits /@ IntegerDigits[ Prime[ Range[31]], 2] (* _Robert G. Wilson v_, Jun 30 2005 *) %o A004676 (Haskell) %o A004676 a004676 = a007088 . a000040 -- _Reinhard Zumkeller_, Aug 06 2012 %o A004676 (PARI) a(n)=subst(Pol(binary(prime(n))), 'x, 10) \\ _Charles R Greathouse IV_, Mar 20 2013 %Y A004676 Cf. A019434 Fermat primes (base 10), A000668 Mersenne primes (base 10). %Y A004676 Cf. A174332, A208238, A208241. %K A004676 nonn,easy,base %O A004676 1,1 %A A004676 _N. J. A. Sloane_