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Prime numbers p = 8n + 7 for which k = (7 * (256^n - 16^n) + n^2) / (n * p) is an integer
2

%I #6 Sep 13 2014 16:50:18

%S 23,31,47,71,79,103,127,151,167,199,223,263,367,439,487,607,631,647,

%T 727,823,887,967,1031,1087,1303,1327,1367,1447,1543,1567,1607,1879,

%U 1951,2207,2311,2503,2647,2671,2887,3079,3271,3463,3527,3607,3727,3847,3967

%N Prime numbers p = 8n + 7 for which k = (7 * (256^n - 16^n) + n^2) / (n * p) is an integer

%H Harvey P. Dale, <a href="/A162587/b162587.txt">Table of n, a(n) for n = 1..1000</a>

%t Transpose[Select[Table[{n,8n+7},{n,500}],PrimeQ[Last[#]]&&IntegerQ[(7*(256^First[ #]-16^First[#])+First[#]^2)/Times@@#]&]][[2]] (* _Harvey P. Dale_, Sep 13 2014 *)

%Y Cf. A162586

%Y Cf. A158034, A158035

%Y Cf. A161896, A161897

%K easy,nonn

%O 1,1

%A _Reikku Kulon_, Jul 07 2009