login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

a(n) is the number of nonzero values of floor (j^2/prime(n)), over 1 <= j < prime(n).
1

%I #17 Sep 07 2024 15:40:41

%S 0,1,2,4,7,9,12,14,18,23,25,30,34,36,40,45,51,53,58,62,64,70,73,79,87,

%T 90,92,96,98,102,115,119,125,127,136,138,144,150,154,159,165,167,177,

%U 179,182,184,196,208,211,213,217,223,225,235,240,246,252,254,260

%N a(n) is the number of nonzero values of floor (j^2/prime(n)), over 1 <= j < prime(n).

%H C. H. Gribble, <a href="/A165994/b165994.txt">Table of n, a(n) for n = 1..78498 (i.e., for primes < 10^6)</a>.

%F a(n) = floor(A000040(n) - sqrt(A000040(n))). - _Jon Maiga_, Nov 13 2018

%t Table[Floor[Prime[n] - Sqrt[Prime[n]]], {n, 60}] (* _Vincenzo Librandi_, Nov 13 2018 *)

%o (Magma) [Floor(NthPrime(n) - Sqrt(NthPrime(n))): n in [1..60]]; // _Vincenzo Librandi_, Nov 13 2018

%Y Cf. A165974.

%K nonn

%O 1,3

%A _Christopher Hunt Gribble_, Oct 03 2009

%E Definition rephrased by _R. J. Mathar_, Oct 09 2009