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 A080166 Primes having initial digits "11" in binary representation. 10
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..20000 EXAMPLE A000040(16)=53 -> '110101' therefore 53 is a term. PROG (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" ")) ) } CROSSREFS 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. Sequence in context: A258349 A089726 A093575 * A116872 A161490 A283587 Adjacent sequences:  A080163 A080164 A080165 * A080167 A080168 A080169 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Feb 03 2003 STATUS approved

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Last modified June 24 21:16 EDT 2019. Contains 324337 sequences. (Running on oeis4.)