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A336117
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Primes of the form q*2^h + 1, where q is a Mersenne prime.
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2
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7, 13, 29, 97, 113, 193, 449, 509, 769, 7937, 12289, 114689, 520193, 786433, 7340033, 8388593, 33292289, 33550337, 469762049, 2130706433, 3221225473, 8588886017, 137438691329, 206158430209, 2199023254529, 6597069766657, 562948879679489, 7881299347898369, 9007182074871809
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OFFSET
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1,1
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LINKS
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FORMULA
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For all n >= 1, A335885(a(n)) <= 2.
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PROG
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(PARI)
isA000668(n) = (isprime(n)&&!bitand(n, 1+n));
isA336117(n) = (isprime(n)&&isA000668(A000265(n-1)));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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