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 A080166 #17 Jul 30 2019 11:17:33
%S A080166 3,7,13,29,31,53,59,61,97,101,103,107,109,113,127,193,197,199,211,223,
%T A080166 227,229,233,239,241,251,389,397,401,409,419,421,431,433,439,443,449,
%U A080166 457,461,463,467,479,487,491,499,503,509,769,773,787,797,809,811,821
%N A080166 Primes having initial digits "11" in binary representation.
%C A080166 Also primes that terminate at 3,2,1 in the x-1 problem: Repeat, if x is even divide by 2 else subtract 1, until 3 is reached. - _Cino Hilliard_, Mar 27 2003
%C A080166 Or, primes in A004760. - _Vladimir Shevelev_, May 04 2009
%H A080166 Alois P. Heinz, <a href="/A080166/b080166.txt">Table of n, a(n) for n = 1..20000</a>
%e A080166 A000040(16)=53 -> '110101' therefore 53 is a term.
%t A080166 Select[Prime[Range[200]],Take[IntegerDigits[#,2],2]=={1,1}&] (* _Harvey P. Dale_, Jul 30 2019 *)
%o A080166 (PARI) pxnm1(n,p) = { forprime(x=2,n, p1 = x; while(p1>1, if(p1%2==0,p1/=2,p1 = p1*p-1;); if(p1 == 3,break); ); if(p1 == 3,print1(x" ")) ) }
%Y A080166 Cf. A004676, A080168.
%Y A080166 Primes whose binary expansion begins with binary expansion of 1, 2, 3, 4, 5, 6, 7: A000040, A080165, A080166, A262286, A262284, A262287, A262285.
%Y A080166 Column k=3 of A262365.
%K A080166 nonn,base
%O A080166 1,1
%A A080166 _Reinhard Zumkeller_, Feb 03 2003