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%I #3 Sep 08 2022 08:45:51
%S 5,6,7,9,11,13,16,19,23,26,39,44,54,61,66,71,83,103,121,143,152,160,
%T 197,238,248,270,313,336,386,403,453,481,512,527,542,619,635,714,752,
%U 804,842,857,898,915,933,1092,1112,1154,1242,1265,1307,1372,1412,1534,1561
%N a(n) = prime index of A048059(n).
%C Indices of primes of the form n^2+n+11.
%C PrimePi(A048059(n)), where PrimePi(k) is the number of primes <= k (A000720).
%C prime(a(n)) = A048059(n).
%F a(n) = A000720(A048059(n)).
%e A048059(7) = 53 is the seventh prime of the form n^2+n+11; 53 has prime index 16 (PrimePi(53) = 16, prime(16) = 53). Hence a(7) = 16.
%o (Magma) PrimePi:=func< n | #PrimesUpTo(n) >; [ PrimePi(p): x in [0..120] | IsPrime(p) where p is x^2+x+11 ];
%Y Cf. A048058 (n^2+n+11), A048097 (n such that n^2+n+11 is prime), A048059 (primes of the form n^2+n+11), A000720 (PrimePi(n), number of primes <= n), A173752.
%K nonn
%O 1,1
%A _Klaus Brockhaus_, Feb 27 2010
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