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Search: id:A131697
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| A131697 |
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Prime averages of two successive perfect prime powers. |
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+0
1
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| 101, 577, 677, 2203, 15877, 22501, 25609, 32401, 42061, 57601, 72901, 181501, 228211, 324901, 378229, 394393, 462409, 695581, 804709, 1664101, 1742401, 1971241, 2873029, 3062509, 3186229, 4137181, 4305661, 4347229, 4804889
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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101 is the average between 81 and 121.
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MATHEMATICA
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a = Select[ Range[2, 10000000], ! PrimeQ[ # ] && Length[FactorInteger[ # ]] == 1 &]; sizea = Length[a]; (a[[Select[Range[sizea - 1], PrimeQ[(a[[ # ]] + a[[ # + 1]])/2] &]]] + a[[Select[Range[sizea - 1], PrimeQ[(a[[ # ]] + a[[ # + 1]])/2] &] + 1]])/2
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CROSSREFS
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Cf. A075455 - Prime averages of two successive perfect powers.
Sequence in context: A142692 A060012 A142507 this_sequence A031423 A089291 A082276
Adjacent sequences: A131694 A131695 A131696 this_sequence A131698 A131699 A131700
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KEYWORD
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nonn
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AUTHOR
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Tanya Khovanova (tanyakh(AT)yahoo.com), Sep 15 2007
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