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%I #30 Sep 08 2022 08:45:05
%S 16,36,100,196,484,676,1156,1444,2116,3364,3844,5476,6724,7396,8836,
%T 11236,13924,14884,17956,20164,21316,24964,27556,31684,37636,40804,
%U 42436,45796,47524,51076,64516,68644,75076,77284,88804,91204,98596
%N a(n) = 4*prime(n)^2.
%C Previous name was: Numbers n such that sum(d|n,(-1)^d) = 3.
%H Vincenzo Librandi, <a href="/A069262/b069262.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = 4*prime(n)^2 = 4*A001248(n).
%F Numbers k such that A048272(k) = -3.
%F Sum_{n>=1} 1/a(n) = P(2)/4, where P is the prime zeta function. - _Amiram Eldar_, Dec 19 2020
%t 4 Prime[Range[40]]^2 (* _Vincenzo Librandi_, Mar 27 2014 *)
%o (Magma) [4*p^2: p in PrimesUpTo(200)]; // _Vincenzo Librandi_, Mar 27 2014
%o (PARI) a(n) = 4*prime(n)^2; \\ _Michel Marcus_, Mar 23 2016
%o (PARI) lista(nn) = {forprime(p=2, nn, print1(4*p^2, ", "));} \\ _Altug Alkan_, Mar 23 2016
%Y Cf. A001248, A048272.
%K easy,nonn
%O 1,1
%A _Benoit Cloitre_, Apr 14 2002
%E New name from existing formula by _Michel Marcus_, Mar 23 2016
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