The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A278234 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A278234

Filter-sequence for factorial base (digit slopes): Least number with the same prime signature as A275734(n).
(history; published version)

#22 by N. J. A. Sloane at Tue Jun 20 23:27:21 EDT 2017

STATUS

reviewed

approved

#21 by Michel Marcus at Tue Jun 20 14:58:34 EDT 2017

STATUS

proposed

reviewed

#20 by Indranil Ghosh at Tue Jun 20 13:42:18 EDT 2017

STATUS

editing

proposed

#19 by Indranil Ghosh at Tue Jun 20 13:41:29 EDT 2017

LINKS

Indranil Ghosh, <a href="/A278234/a278234_1.txt">Python program for computing this sequence</a>

#18 by Indranil Ghosh at Tue Jun 20 13:41:09 EDT 2017

LINKS

Indranil Ghosh, <a href="/A278234/a278234.txt">Python program for computing this sequence</a>

Indranil Ghosh, <a href="/A278234/a278234_1.txt">Python program for computing this sequence</a>

#17 by Indranil Ghosh at Tue Jun 20 13:38:26 EDT 2017

LINKS

Indranil Ghosh, <a href="/A278234/a278234.txt">Python program for computing this sequence</a>

#16 by Indranil Ghosh at Tue Jun 20 13:38:03 EDT 2017

LINKS

Indranil Ghosh, <a href="/A278234/a278234.txt">Python program for computing this sequence</a>

STATUS

approved

editing

#15 by N. J. A. Sloane at Sat Nov 19 08:28:53 EST 2016

STATUS

proposed

approved

#14 by Antti Karttunen at Fri Nov 18 18:04:18 EST 2016

STATUS

editing

proposed

#13 by Antti Karttunen at Fri Nov 18 16:59:51 EST 2016

COMMENTS

This sequence works as a "sentinel" can be used for many filtering certain factorial base (A007623) related sequences by matching to , because it matches only with any such sequence b that is obtained can be computed as b(n) = f(A275734(n)), where f(n) is any function that depends only on the prime signature of n (see some of these are listed under the index entry for "sequences computed from exponents in ...").

Matching in this context means that the sequence a matches with the sequence b iff for all i, j: a(i) = a(j) => b(i) = b(j). In other words, iff the sequence b partitions the natural numbers to the same or coarser equivalence classes (as/than the sequence a) by the distinct values it obtains.

CROSSREFS

Cf. A007623, A046523, A225901, A275734.

Other factorial base related filter-sequences related to factorial base: A278225, A278235, A278236.

Discussion

Fri Nov 18

17:30

Antti Karttunen: PLEASE, do not shorten any of these filtering-sequences (unless absolutely must!). I have on purpose included enough terms to fill up to about 360 characters (which will nicely show as four full lines when the entry is shown to the user), so that less false positives will be generated when an automatic matching program is run with this sequence.