1,23

a(n) = #{k: A048992(k)<=n} = n - #{k: A048991(k)<=n};

a(n) < n/2 for n < 740; a(n) > n/2 for 740 < n < 1260,

see A105391 for numbers m with a(m) = m/2.

Klaus Brockhaus, Table of n, a(n) for n = 1..6000

Klaus Brockhaus, Plots of A105390(n)/n at various scales

(JBASIC, from Klaus Brockhaus, Aug 15 2007)

s$ = "" : d = 0

FOR n = 1 TO 100

sn$ = str$(n)

IF instr(s$, sn$) > 0 THEN d = d+1 ELSE s$ = s$ + sn$

print d ; ", ";

NEXT

Cf. A048991, A048992, A105391, A131981.

Sequence in context: A279041 A072746 A179528 * A013941 A061798 A029241

Adjacent sequences: A105387 A105388 A105389 * A105391 A105392 A105393

nonn,base

Reinhard Zumkeller, Apr 04 2005

approved