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A080166
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Primes having initial digits "11" in binary representation.
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3
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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; internal format)
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OFFSET
| 1,1
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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. [From Vladimir Shevelev (shevelev(AT)bgu.ac.il), May 04 2009]
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EXAMPLE
| A000040(16)=53 -> '110101' therefore 53 is a term.
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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" ")) ) }
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CROSSREFS
| Cf. A004676, A080165, A080168.
Sequence in context: A146432 A089726 A093575 * A116872 A161490 A134270
Adjacent sequences: A080163 A080164 A080165 * A080167 A080168 A080169
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KEYWORD
| nonn,base
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 03 2003
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