A089245 Integer part of square root of the reciprocal of a number multiplied by 10 to the power of the integer part of the square root of the number.

10, 7, 5, 50, 44, 40, 37, 35, 333, 316, 301, 288, 277, 267, 258, 2500, 2425, 2357, 2294, 2236, 2182, 2132, 2085, 2041, 20000, 19611, 19245, 18898, 18569, 18257, 17960, 17677, 17407, 17149, 16903, 166666, 164398, 162221, 160128, 158113, 156173

Offset

1,1

Comments

The sum of the reciprocals = 0.595091701724608076103001212.. Converges rapidly.

Links

Table of n, a(n) for n=1..41.

Formula

floor( sqrt(1/x)*10^(floor(sqrt(x))) )

Mathematica

Table[Floor[Sqrt[1/x] 10^Floor[Sqrt[x]]], {x, 50}] (* Harvey P. Dale, Feb 01 2022 *)

Prog

(PARI) rootrecip(n) = { sr=0; for(x=1, n, r =sqrt(x); ip=floor(r); fp=r-ip; y=floor((1/r)*10^ip); print1(y", "); sr = sr + 1.0/y; ); print(); print(sr) }

Crossrefs

Sequence in context: A332980 A246662 A246651 * A343540 A343551 A098592

Adjacent sequences: A089242 A089243 A089244 * A089246 A089247 A089248

Keyword

easy,nonn

Author

Cino Hilliard, Dec 11 2003

Status

approved