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A152466
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a(1) = 252, a(n) is a(n-1) multiplied by the smallest prime factor of a(n-1)+1.
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252, 2772, 130284, 651420, 219528540, 257067920340, 4370154645780, 292800361267260, 11023640801351071740, 13475008472558425746927448860, 5107028211099643358085503117940, 1313771981231475489737485570488833367540
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Conjecture: this sequence will never have any numbers k where k+1 is prime. (All similar sequences that start with numbers less than 252 are known to have numbers k where k+1 is prime.)
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EXAMPLE
| First term is 252. Smallest prime factor of 253 is 11, so next term is 252 * 11 = 2772.
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MATHEMATICA
| a = {252}; Do[AppendTo[a, a[[ -1]]*FactorInteger[a[[ -1]] + 1][[1, 1]]], {10}]; a [From Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 06 2008]
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CROSSREFS
| Sequence in context: A166783 A104679 A117281 * A004535 A027815 A184498
Adjacent sequences: A152463 A152464 A152465 * A152467 A152468 A152469
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KEYWORD
| nonn
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AUTHOR
| J. Lowell (jhbubby(AT)mindspring.com), Dec 05 2008
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EXTENSIONS
| More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 06 2008
Extended by Max Alekseyev (maxale(AT)gmail.com), Sep 19 2009
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