A136241 - OEIS

%I #6 Jan 20 2019 13:11:49

%S 2,4,6,10,16,28,30,46,60,66,70,96,100,126,130,138,148,180,196,240,268,

%T 306,330,358,378,396,408,418,420,448,456,478,486,490,598,606,616,618,

%U 640,646,676,708,750,786,838,856,906,946,966,976,996,1050,1060,1090

%N Numbers n among A006093 such that n^2 + n - 1 is prime.

%H Harvey P. Dale, <a href="/A136241/b136241.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A091567(n) - 1.

%t Select[Prime[Range[200]]-1,PrimeQ[#^2+#-1]&] (* _Harvey P. Dale_, Jan 20 2019 *)

%Y Cf. A136240, A091568.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, Dec 23 2007