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A000040(n+1) - A073273(n).
3

%I #12 Jun 02 2015 15:28:07

%S 0,1,0,2,0,2,0,0,3,-1,2,2,0,0,1,3,-1,2,2,-1,2,0,0,3,2,0,2,0,-4,6,0,3,

%T -3,5,-1,1,2,0,1,3,-3,5,0,2,-4,1,5,2,0,0,3,-3,3,1,1,3,-1,2,2,-3,-1,6,

%U 2,0,-4,5,-1,5,0,0,0,2,1,2,0,0,3,-1,0,5,-3,5,-1,2,0,0,3,2,0,-3,3,3,-1,3

%N A000040(n+1) - A073273(n).

%H Charles R Greathouse IV, <a href="/A073274/b073274.txt">Table of n, a(n) for n = 1..10000</a>

%e For n=11, A000040(11)*A000040(13) = 31*41 = 1271 = 35*35+46, therefore A073273(11)=35; a(11) = A000040(12)-A073273(11) = 37-35 = +2.

%o (PARI) vector(80, n, prime(n+1) - floor(sqrt(prime(n)*prime(n+2)))) \\ _Michel Marcus_, Jun 02 2015

%o (PARI) a(n,p=prime(n))=my(q=nextprime(p+1),r=nextprime(q+1)); q - sqrtint(p*r) \\ _Charles R Greathouse IV_, Jun 02 2015

%Y Cf. A073272.

%K sign

%O 1,4

%A _Reinhard Zumkeller_, Jul 22 2002