A094473 Smallest prime factor of 2^n+3^n.
5, 13, 5, 97, 5, 13, 5, 17, 5, 13, 5, 97, 5, 13, 5, 3041, 5, 13, 5, 41, 5, 13, 5, 17, 5, 13, 5, 97, 5, 13, 5, 1153, 5, 13, 5, 97, 5, 13, 5, 17, 5, 13, 5, 89, 5, 13, 5, 193, 5, 13, 5, 97, 5, 13, 5, 17, 5, 13, 5, 41, 5, 13, 5, 769, 5, 13, 5, 97, 5, 13, 5, 17, 5, 13, 5
Offset: 1
Keywords
Links
- Antti Karttunen, Table of n, a(n) for n = 1..1023
Programs
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GAP
List([1..80],n->Factors(2^n+3^n)[1]); # Muniru A Asiru, Nov 01 2018
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Magma
[Min(PrimeFactors(2^n+3^n)): n in[1..100]]; // Vincenzo Librandi, Dec 23 2019
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Magma
[PrimeFactors(2^n+3^n)[1]: n in[1..600]]; // Bruno Berselli, Dec 23 2019
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Mathematica
mif[x_]:=Part[Flatten[FactorInteger[x]], 1] Table[mif[2^w+3^w], {w, 1, 75}] FactorInteger[#][[1,1]]&/@Table[2^n+3^n,{n,80}] (* Harvey P. Dale, Mar 26 2019 *) -
PARI
a(n)=factor(2^n+3^n)[1,1] \\ Charles R Greathouse IV, Apr 29 2015
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PARI
A094473(n) = { my(k=(2^n+3^n)); forprime(p=2,k,if(!(k%p),return(p))); }; \\ Antti Karttunen, Nov 01 2018
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