The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A174898

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A174898

a(n) = characteristic function of numbers k such that A007955(m) = k has no solution for any m, where A007955(m) = product of divisors of m.
(history; published version)

#12 by Alois P. Heinz at Fri Oct 20 14:26:57 EDT 2017

STATUS

proposed

approved

#11 by Michel Marcus at Fri Oct 20 13:48:12 EDT 2017

STATUS

editing

proposed

#10 by Michel Marcus at Fri Oct 20 13:45:30 EDT 2017

COMMENTS

a(n) = characteristic function of numbers from A174896(n). a(n) = 1 if A007955(m) not equal to n for any m, else 0.

a(n) = 1 if A007955(m) not equal to n for any m, else 0.

STATUS

proposed

editing

#9 by Antti Karttunen at Fri Oct 20 13:40:29 EDT 2017

STATUS

editing

proposed

#8 by Antti Karttunen at Fri Oct 20 13:36:09 EDT 2017

LINKS

Antti Karttunen, <a href="/A174898/b174898.txt">Table of n, a(n) for n = 1..20000</a> (computed from the b-file of A174897)

<a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

CROSSREFS

Cf. A007955, A174896, A174897.

#7 by Antti Karttunen at Fri Oct 20 13:32:35 EDT 2017

DATA

0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1

EXTENSIONS

More terms from Antti Karttunen, Oct 20 2017

STATUS

approved

editing

#6 by R. J. Mathar at Wed Sep 18 04:47:43 EDT 2013

STATUS

editing

approved

#5 by R. J. Mathar at Wed Sep 18 04:47:25 EDT 2013

COMMENTS

a(n) = characteristic function of numbers from A174896(n). a(n) = 1 if A007955(m) not equal to n for any m, else 0. a(n) + A174897(n) = A000012(n).

STATUS

proposed

editing

#4 by Michel Marcus at Wed Sep 18 00:16:17 EDT 2013

STATUS

editing

proposed

Discussion

Wed Sep 18

00:22

Tom Edgar: I am concerned that the formula you have entered for this and A174897 are circular and so perhaps yours should also be a comment?

00:32

Michel Marcus: I really don't know.

#3 by Michel Marcus at Wed Sep 18 00:04:02 EDT 2013

FORMULA

a(n) = 1 - A174897(n).

STATUS

approved

editing

Discussion

Wed Sep 18

00:06

Michel Marcus: Wonder if initial formula should be kept in comments ?