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A132635 Number of primes, 0's, and 1's in [0, n^2). 0

%I #12 Apr 06 2020 00:20:19

%S 0,1,4,6,8,11,13,17,20,24,27,32,36,41,46,50,56,63,68,74,80,87,94,101,

%T 107,116,124,131,139,148,156,164,174,183,193,202,212,221,230,242,253,

%U 265,276,285,297,308,321,331,344,359,369,380,395,411,423,436,447,459,476

%N Number of primes, 0's, and 1's in [0, n^2).

%C Number of p-adic cyclotomic type levels in A_n-1 or SU(n).

%F a(n) = pi(n^2) + 2 = A038107(n) + 2, n > 1. [_Charles R Greathouse IV_, Nov 07 2011]

%e SU(5) at n^2-1=24 is exactly inside SU(9) at n^2-1=80.

%t Table[Sum[If[m == 0 || m == 1, 1, If[PrimeQ[m], 1, 0]], {m, 0,n^2 - 1}], {n, 0, 30}]

%o (PARI) a(n)=if(n<2,n,primepi(n^2)+2) \\ _Charles R Greathouse IV_, Nov 07 2011

%K nonn,easy

%O 0,3

%A _Roger L. Bagula_ and _Gary W. Adamson_, Aug 26 2008

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Last modified July 28 10:08 EDT 2024. Contains 374686 sequences. (Running on oeis4.)