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A063038 a(n) = floor(n*sqrt(n)) - d(n), where d(n) is the number of divisors function. 0

%I #15 Apr 13 2024 14:58:44

%S 0,0,3,5,9,10,16,18,24,27,34,35,44,48,54,59,68,70,80,83,92,99,108,109,

%T 122,128,136,142,154,156,170,175,185,194,203,207,223,230,239,244,260,

%U 264,279,285,295,307,320,322,340,347,360,368,383,388,403,411,426,437

%N a(n) = floor(n*sqrt(n)) - d(n), where d(n) is the number of divisors function.

%F a(n) = A000093(n) - A000005(n). - _Michel Marcus_, Apr 13 2024

%t Table[Floor[n*Sqrt[n]] - DivisorSigma[0, n], {n, 50}] (* _Wesley Ivan Hurt_, Jun 09 2014 *)

%o (PARI) j=[]; for(n=1,100,j=concat(j,floor(n*sqrt(n))-numdiv(n))); j

%Y Cf. A000005, A000093, A055682.

%K easy,nonn,changed

%O 1,3

%A _Jason Earls_, Aug 03 2001

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Last modified April 25 07:07 EDT 2024. Contains 371964 sequences. (Running on oeis4.)