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A216146 Smallest prime factor of 3*(2n+1)^(2n+1) + 2. 2

%I #7 Feb 03 2014 12:22:28

%S 5,83,9377,2470631,97,5,29,13,306503,23173,5,7,7,11,12517,5,13,61,17,

%T 71,5,53,1531477446517,97,101,5,11,1999,53,11,5,67153,7,7,13499,5,13,

%U 28201

%N Smallest prime factor of 3*(2n+1)^(2n+1) + 2.

%H Factor DB, <a href="http://factordb.com/index.php?query=3*(2*n%2B1)^(2*n%2B1)%2B2">3*(2*n+1)^(2*n+1)+2</a>.

%e Indices n = 0,1,2,3 correspond to the 4 primes a(n) = 3*(2n+1)^(2n+1) + 2, and to A160360(2,3,4,5) = 1,3,5,7. The next prime is a(46), with 184 digits too large to be displayed here.

%e a(22)=1531477446517 is the smaller factor of the semiprime 3*45^45+2.

%o (PARI) forstep(n=1,300,2,forprime(p=1,default(primelimit),Mod(n,p)^n*3+2&next;print1(p",");next(2));print1(factor(3*n^n+2)[1,1]","))

%Y Cf. A160360.

%K nonn

%O 0,1

%A _M. F. Hasler_, Sep 02 2012

%E Comment in example and link added by _M. F. Hasler_, Feb 03 2014

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Last modified April 27 05:20 EDT 2024. Contains 372009 sequences. (Running on oeis4.)