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A127959
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Nonprime numbers of the form 1 + Sum_{k=1..m} [2^(2k-1]].
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0
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171, 10923, 699051, 11184811, 44739243, 178956971, 2863311531, 11453246123, 45812984491, 183251937963, 733007751851, 11728124029611, 46912496118443, 187649984473771, 750599937895083, 3002399751580331, 12009599006321323
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Prime numbers of the form 1+Sum[2^(2n-1]] is A000979. Numbers x such 1+Sum[2^(2n-1]] is prime for n=1,2,...,x is A127936. A127955 is probably a subset of the present sequence..
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MATHEMATICA
| a = {}; Do[c = 1 + Sum[2^(2n - 1), {n, 1, x}]; If[PrimeQ[c] == False, AppendTo[a, c]], {x, 1, 50}]; a
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CROSSREFS
| Cf. A000979, A000978, A124400, A126614, A127955, A127956, A127957, A127958, A127936.
Sequence in context: A016058 A152926 A206595 * A046166 A145625 A097844
Adjacent sequences: A127956 A127957 A127958 * A127960 A127961 A127962
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KEYWORD
| nonn
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AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Feb 09 2007
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