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Search: id:A073924
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| A073924 |
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Smallest power of 2 that is greater than the previous term such that every partial sum (n>1) is a prime. |
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+0
8
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| 1, 2, 4, 16, 128, 65536, 9007199254740992, 73786976294838206464, 205688069665150755269371147819668813122841983204197482918576128
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Next term is too large to include.
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EXAMPLE
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a(5) is 128 because it is the next power of 2 greater than 16 such that 1+2+4+16+x is prime.
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MATHEMATICA
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a[1] = 1; a[n_] := Block[{k = a[n - 1] + 1, s = Plus @@ (2^Array[a, n - 1])}, While[ !PrimeQ[s + 2^k], k++ ]; k]; Array[2^a[ # ] &, 9] (from Robert G. Wilson v (rgwv(at)rgwv.com), Jan 31 2006)
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CROSSREFS
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Cf. A073923.
Sequence in context: A047892 A009200 A144526 this_sequence A061588 A050472 A109457
Adjacent sequences: A073921 A073922 A073923 this_sequence A073925 A073926 A073927
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 19 2002
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EXTENSIONS
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More terms from Jason Earls (zevi_35711(AT)yahoo.com), Sep 03 2002
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