A027662 a(n)/1000 gives sqrt(n) to 3 places after the decimal point.

1000, 1414, 1732, 2000, 2236, 2449, 2646, 2828, 3000, 3162, 3317, 3464, 3606, 3742, 3873, 4000, 4123, 4243, 4359, 4472, 4583, 4690, 4796, 4899, 5000, 5099, 5196, 5292, 5385, 5477, 5568, 5657, 5745, 5831, 5916, 6000, 6083, 6164, 6245, 6325, 6403, 6481, 6557, 6633

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base

Crossrefs

Cf. A027661, A027663, A027664.

Programs

Maple

lprint(round(evalf(1000*sqrt(n))));

Mathematica

Table[Floor[1000*Sqrt[n]+1/2],{n,40}]  (* Harvey P. Dale, Apr 22 2011 *)

Python

from math import isqrt
def A027662(n): return (m:=isqrt(k:=n*10**6))+int((k-m*(m+1)<<2)>=1) # Chai Wah Wu, Jul 30 2022