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%I #9 Oct 08 2012 17:58:44
%S 15,50,80,110,230,245,425,570,635,645,710,925,1440,1645,1710,1815,
%T 2000,2465,2635,2940,3040,3090,3195,3525,4260,4310,4400,4885,5960,
%U 6145,7030,7120,7250,8430,8890,9445,10265,11060,11150,11710,11775,13020,13565
%N Numbers n such that f[n],f[n+1]and f[n+2] are all primes, where f[n]=8*n^2+4*n+1.
%C All terms are divisible by 5, hence conjecture: there is no such n that f[n],f[n+1],f[n+2] and f[n+3] are primes.
%H Harvey P. Dale, <a href="/A103777/b103777.txt">Table of n, a(n) for n = 1..1000</a>
%e 15 is a term because f[15]=1861, f[16]=2113 and f[17]=2381 are all primes.
%t Flatten[Position[Partition[Table[PrimeQ[8n^2+4n+1],{n,14000}],3,1],{True,True,True}]] (* _Harvey P. Dale_, Oct 08 2012 *)
%Y Cf. A102083, A103776.
%K nonn
%O 1,1
%A _Zak Seidov_, Feb 15 2005