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A073273 a(n) = floor(sqrt(prime(n)*prime(n+2))).

%I A073273 #18 Sep 08 2022 08:45:06
%S A073273 3,4,7,9,13,15,19,23,26,32,35,39,43,47,52,56,62,65,69,74,77,83,89,94,
%T A073273 99,103,105,109,117,121,131,134,142,144,152,156,161,167,172,176,184,
%U A073273 186,193,195,203,210,218,225,229,233,236,244,248,256,262,266,272,275
%N A073273 a(n) = floor(sqrt(prime(n)*prime(n+2))).
%C A073273 A000040(n) < a(n) < A000040(n+2).
%H A073273 Amiram Eldar, <a href="/A073273/b073273.txt">Table of n, a(n) for n = 1..10000</a>
%F A073273 a(n) = A098090(A028310(n - 1)) + A089038(n). - _Miko Labalan_, Dec 12 2015
%e A073273 prime(10)*prime(12) = 29*37 = 1073 = 32*32+49, therefore a(10)=32; A073274(10) = prime(11)-a(10) = 31-32 = -1.
%t A073273 Table[Floor[Sqrt[Prime[n] Prime[n + 2]]], {n, 60}] (* _Vincenzo Librandi_, Dec 12 2015 *)
%o A073273 (Magma) [Floor(Sqrt(NthPrime(n)*NthPrime(n+2))): n in [1..60]]; // _Vincenzo Librandi_, Dec 12 2015
%o A073273 (PARI) a(n) = sqrtint(prime(n)*prime(n+2)); \\ _Michel Marcus_, Dec 12 2015
%Y A073273 Cf. A000040, A073271, A073274, A078444.
%K A073273 nonn
%O A073273 1,1
%A A073273 _Reinhard Zumkeller_, Jul 22 2002