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A104335 Positive integers n such that n^14 + 1 is semiprime (A001358). 13
4, 74, 94, 116, 270, 464, 556, 654, 1140, 1156, 1246, 1306, 1736, 2464, 2470, 2604, 2804, 2836, 2900, 3054, 3890, 4006, 4056, 4330, 4736, 4780, 5016, 5294, 5340, 5486, 5700, 5834, 6434, 7114, 7304, 8626, 8880, 9164, 9546, 9744, 9980, 10086, 10166 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
x^14+1 has factors (1 + x^2) (1 - x^2 + x^4 - x^6 + x^8 - x^10 + x^12).
LINKS
EXAMPLE
4^14 + 1 = 268435457 = 17 * 15790321,
74^14 + 1 = 147653612273582215982104577 = 5477 * 26958848324553992328301,
1140^14 + 1 = 6261349103849104148619671961600000000000001 = 1299601 * 4817901112610027345792802530622860401.
MATHEMATICA
Select[ Range[2, 10422, 2], PrimeQ[ #^2 + 1] && PrimeQ[ #^12 - #^10 + #^8 - #^6 + #^4 - #^2 + 1] &] (*Robert G. Wilson v, Apr 18 2005 *)
Select[Range[2, 10200, 2], PrimeOmega[#^14+1]==2&] (* Harvey P. Dale, Oct 16 2011 *)
CROSSREFS
Sequence in context: A353740 A090212 A137046 * A156494 A232371 A114878
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Apr 17 2005
EXTENSIONS
More terms from Robert G. Wilson v, Apr 18 2005
STATUS
approved

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Last modified July 24 15:09 EDT 2024. Contains 374584 sequences. (Running on oeis4.)