

A100618


Initially there are n people in a room. At each step, if there are currently M people in the room, [M/k^2] of them leave, for k = 2, 3, ... Sequence gives number who are left at the end.


4



1, 2, 3, 3, 4, 5, 6, 6, 7, 8, 8, 8, 9, 10, 11, 11, 12, 13, 14, 14, 15, 15, 15, 15, 16, 17, 18, 18, 19, 20, 21, 21, 22, 23, 23, 23, 24, 24, 25, 25, 26, 27, 28, 28, 29, 29, 29, 29, 30, 31, 32, 32, 33, 34, 35, 35, 35, 36, 36, 36, 37, 38, 39, 39, 40, 41, 42, 42, 43, 43, 43, 43, 44, 45, 46, 46
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

If [M/k^2] is changed to [M/k] we get A100617.


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


EXAMPLE

10 > 10  [10/4] = 8 > 8  [8/9] = 8, which is now fixed, so a(10) = 8.


MAPLE

f:=proc(n) local i, j, k; k:=n; for i from 2 to 10000 do j := floor(k/(i^2)); if j < 1 then break; fi; k := kj; od; k; end;


MATHEMATICA

a[n_] := (k = 2; FixedPoint[#  Floor[#/(k++)^2]&, n]); Table[a[n], {n, 1, 100}] (* JeanFrançois Alcover, Feb 10 2018 *)


PROG

(Haskell)
a100618 n = f 2 n where
f k n  n' == 0 = n
 otherwise = f (k+1) (nn') where n' = div n (k^2)
 Reinhard Zumkeller, Sep 15 2011


CROSSREFS

Cf. A250007 (run lengths).
Sequence in context: A025556 A005229 A091245 * A248227 A061288 A086525
Adjacent sequences: A100615 A100616 A100617 * A100619 A100620 A100621


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Dec 03 2004


STATUS

approved



