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A127956
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Prime numbers p such that (2^p+1)/3 is composite.
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11
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29, 37, 41, 47, 53, 59, 67, 71, 73, 83, 89, 97, 103, 107, 109, 113, 131, 137, 139, 149, 151, 157, 163, 173, 179, 181, 193, 197, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 317, 331, 337, 349, 353, 359, 367, 373
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| If p-1 is squarefree, 2a(n) is the multiplicative order of 2 modulo every divisor d>1 of (2^p+1)/3. - Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jul 15 2008
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MATHEMATICA
| a = {}; Do[c = (2^Prime[x] + 1)/3; If[PrimeQ[c] == False, AppendTo[a, Prime[x]]], {x, 2, 100}]; a
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CROSSREFS
| Cf. A000979, A000978, A124400, A126614, A127955, A127957.
Sequence in context: A134254 A089296 A089297 * A166088 A172195 A161724
Adjacent sequences: A127953 A127954 A127955 * A127957 A127958 A127959
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KEYWORD
| nonn
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AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Feb 09 2007
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