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 A104494 Positive integers n such that n^17 + 1 is semiprime (A001358). 14
 2, 58, 66, 166, 268, 270, 408, 600, 672, 808, 822, 970, 1050, 1090, 1150, 1200, 1212, 1380, 1578, 1752, 1912, 1950, 1986, 2016, 2038, 2292, 2340, 2548, 2590, 2656, 2718, 2800, 2856, 3162, 3300, 3342, 3738, 4138, 4152, 4228, 4270, 4272, 4362, 4782, 5080, 5166 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Price, Table of n, a(n) for n = 1..1000 FORMULA a(n)^17 + 1 is semiprime (A001358). EXAMPLE 2^17 + 1 = 131073 = 3 * 43691, 58^17 + 1 = 951208868148684143308060622849 = 59 * 16122184205909900734034925811, 66^17 + 1 = 8555529718761317069203003539457 = 67 * 127694473414348015958253784171, 1050^17 + 1 = 2292018317801032401637344360351562500000000000000001 = 1051 * 2180797638250268698037435166842590390104662226451. MATHEMATICA Select[Range[1000000], PrimeQ[# + 1] && PrimeQ[(#^17 + 1)/(# + 1)] &] (* Robert Price, Mar 10 2015 *) Select[Range[5200], PrimeOmega[#^17+1]==2&] (* Harvey P. Dale, Mar 07 2017 *) PROG (PARI) for(n=1, 3000, if(!ispseudoprime(n^17+1), forprime(p=1, 10^4, if((n^17+1)%p==0, if(ispseudoprime((n^17+1)/p), print1(n, ", ")); break)))) \\ Derek Orr, Mar 09 2015 (Magma) IsSemiprime:=func< n | &+[ k[2]: k in Factorization(n) ] eq 2 >; [n: n in [1..1200]|IsSemiprime(n^17+1)]; // Vincenzo Librandi, Mar 10 2015 CROSSREFS Cf. A001358, A006313, A103854, A104238, A104335, A105041, A105066, A105078, A105122, A105142, A105237, A104479. Sequence in context: A030263 A359242 A090743 * A121931 A343578 A156507 Adjacent sequences: A104491 A104492 A104493 * A104495 A104496 A104497 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, Apr 19 2005 EXTENSIONS a(14)-a(46) from Robert Price, Mar 09 2015 STATUS approved

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Last modified March 1 14:57 EST 2024. Contains 370433 sequences. (Running on oeis4.)