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%I #30 Sep 08 2022 08:44:34
%S 1,4,16,36,100,144,256,324,484,784,900,1296,1600,1764,2116,2704,3364,
%T 3600,4356,4900,5184,6084,6724,7744,9216,10000,10404,11236,11664,
%U 12544,15876,16900,18496,19044,21904
%N a(n) = (prime(n) - 1)^2.
%H Vincenzo Librandi, <a href="/A005722/b005722.txt">Table of n, a(n) for n = 1..1000</a>
%H Richard K. Guy, <a href="/A005712/a005712.pdf">Letter to N. J. A. Sloane, 1987</a>.
%F a(n) = A192134(A095874(A001248(n))) - 1. - _Reinhard Zumkeller_, Jun 26 2011
%F a(n) = A006093(n)^2. - _Wesley Ivan Hurt_, Mar 27 2014
%F Sum_{n>=1} 1/a(n) = A086242. - _Amiram Eldar_, Nov 09 2020
%F From _Amiram Eldar_, Jan 23 2021: (Start)
%F Product_{n>=1} (1 + 1/a(n)) = A065485.
%F Product_{n>=2} (1 - 1/a(n)) = A005597. (End)
%p A005722:=n->(ithprime(n)-1)^2; seq(A005722(n), n=1..40); # _Wesley Ivan Hurt_, Mar 27 2014
%t Table[(Prime[n] - 1)^2, {n, 40}] (* _Vincenzo Librandi_, Mar 27 2014 *)
%o (Magma) [(p-1)^2: p in PrimesUpTo(200)]; // _Vincenzo Librandi_, Mar 27 2014
%o (PARI) a(n) = (prime(n) - 1)^2; \\ _Michel Marcus_, Nov 09 2020
%Y Cf. A001248, A005597, A006093, A065485, A086242, A095874, A192134.
%K nonn,easy
%O 1,2
%A Scorpion(AT)aol.com
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