A080168 -id:A080168 - cp's OEIS frontend

A080166 Primes having initial digits "11" in binary representation.

3, 7, 13, 29, 31, 53, 59, 61, 97, 101, 103, 107, 109, 113, 127, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 769, 773, 787, 797, 809, 811, 821

Offset: 1

Reinhard Zumkeller, Feb 03 2003

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

Or, primes in A004760. - Vladimir Shevelev, May 04 2009

			A000040(16)=53 -> '110101' therefore 53 is a term.

Alois P. Heinz, Table of n, a(n) for n = 1..20000

Cf. A004676, A080168.
Primes whose binary expansion begins with binary expansion of 1, 2, 3, 4, 5, 6, 7: A000040, A080165, A080166, A262286, A262284, A262287, A262285.
Column k=3 of A262365.

Select[Prime[Range[200]],Take[IntegerDigits[#,2],2]=={1,1}&] (* Harvey P. Dale, Jul 30 2019 *)

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" ")) ) }

cp's OEIS Frontend

A080166 Primes having initial digits "11" in binary representation.

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