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A138402 a(n) = (n-th prime)^4-(n-th prime)^2.

%I A138402 #23 Nov 22 2022 02:34:52
%S A138402 12,72,600,2352,14520,28392,83232,129960,279312,706440,922560,1872792,
%T A138402 2824080,3416952,4877472,7887672,12113880,13842120,20146632,25406640,
%U A138402 28392912,38943840,47451432,62734320,88519872,104050200,112540272
%N A138402 a(n) = (n-th prime)^4-(n-th prime)^2.
%H A138402 Vincenzo Librandi, <a href="/A138402/b138402.txt">Table of n, a(n) for n = 1..200</a>
%H A138402 <a href="/index/Pri#prime_powers">Index to sequences related to prime powers</a>.
%F A138402 Product_{n>=1} (1 - 1/a(n)) = A065471.
%F A138402 From _Amiram Eldar_, Nov 22 2022: (Start)
%F A138402 a(n) = A001248(n) * A084920(n).
%F A138402 a(n) = A036689(n) * A036690(n). (End)
%t A138402 a = {}; Do[p = Prime[n]; AppendTo[a, p^4 - p^2], {n, 1, 50}]; a
%t A138402 #^4-#^2&/@Prime[Range[30]] (* _Harvey P. Dale_, Sep 19 2018 *)
%o A138402 (PARI) forprime(p=2,1e3,print1(p^4-p^2", ")) \\ _Charles R Greathouse IV_, Jun 16 2011
%o A138402 (PARI) apply(p->p^4-p^2, primes(100)) \\ _Charles R Greathouse IV_, Apr 17 2015
%o A138402 (Magma) [NthPrime((n))^4 - NthPrime((n))^2: n in [1..30] ]; // _Vincenzo Librandi_, Jun 17 2011
%Y A138402 Cf. A001248, A036689, A036690, A065471, A084920.
%K A138402 nonn,easy
%O A138402 1,1
%A A138402 _Artur Jasinski_, Mar 19 2008