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a(n) = 5^prime(n) - 3^prime(n) + 2^prime(n).
1

%I #17 Sep 08 2022 08:45:32

%S 20,106,2914,76066,48653026,1219116994,762810444034,19072324590946,

%T 11920834820287906,186264446293255209154,4656612255406143777826,

%U 72759575691550490581159234,45474735052173417717604422274,1136868376887903338795354772706,710542735733511371652904252645666

%N a(n) = 5^prime(n) - 3^prime(n) + 2^prime(n).

%H Vincenzo Librandi, <a href="/A135174/b135174.txt">Table of n, a(n) for n = 1..200</a>

%F a(n)= 5^A000040(n) - 3^A000040(n) + 2^A000040(n).

%e a(4)=76066 because the 4th prime number is 7, 5^7=78125, 3^7=2187, 2^7=128 and 78125-2187+128=76066.

%t Table[5^p-3^p+2^p,{p,Prime[Range[20]]}] (* _Harvey P. Dale_, Dec 12 2013 *)

%o (Magma) [5^p-3^p+2^p: p in PrimesUpTo(100)]; // _Vincenzo Librandi_, Dec 14 2010

%Y Cf. A000040.

%Y Cf. 2^p: A034785; 3^p: A057901; 5^p: A057902.

%K nonn,easy

%O 1,1

%A _Omar E. Pol_, Nov 25 2007

%E More terms from _Vincenzo Librandi_, Dec 14 2010