A105390 Number of Hannah Rollman's numbers <= n.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 9, 10, 10, 10, 11, 11, 11, 11, 11, 12, 13, 14, 15, 15, 15, 16, 16, 16, 16, 17, 18, 19, 20, 21, 21, 21, 22, 22, 22, 23, 24, 25, 26, 27, 28, 28

Offset

1,23

Comments

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.

Links

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

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

Prog

(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

Crossrefs

Cf. A048991, A048992, A105391, A131981.

Sequence in context: A279041 A072746 A179528 * A347941 A013941 A061798

Adjacent sequences: A105387 A105388 A105389 * A105391 A105392 A105393

Keyword

nonn,base

Author

Reinhard Zumkeller, Apr 04 2005

Status

approved