The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A286107 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A286107

a(1) = 0, for n > 1, if A286106(n) > 0, then a(n) = A285735(n), otherwise a(n) = A285734(n).
(history; published version)

#17 by Michel Marcus at Fri Apr 30 06:05:26 EDT 2021

STATUS

reviewed

approved

#16 by Joerg Arndt at Fri Apr 30 06:01:09 EDT 2021

STATUS

proposed

reviewed

#15 by F. Chapoton at Fri Apr 30 05:54:11 EDT 2021

STATUS

editing

proposed

#14 by F. Chapoton at Fri Apr 30 05:54:04 EDT 2021

PROG

j=int(n//2)

print ([a286107(n) for n in range(1, 121)] ) # Indranil Ghosh, May 02 2017

STATUS

approved

editing

Discussion

Fri Apr 30

05:54

F. Chapoton: adapt py code to py3

#13 by N. J. A. Sloane at Sat Dec 07 12:18:29 EST 2019

PROG

print [a286107(n) for n in xrangerange(1, 121)] # Indranil Ghosh, May 02 2017

Discussion

Sat Dec 07

12:18

OEIS Server: https://oeis.org/edit/global/2837

#12 by N. J. A. Sloane at Tue May 02 20:50:48 EDT 2017

STATUS

proposed

approved

#11 by Indranil Ghosh at Tue May 02 15:05:43 EDT 2017

STATUS

editing

proposed

#10 by Indranil Ghosh at Tue May 02 15:05:35 EDT 2017

PROG

(Python)

from sympy.ntheory.factor_ import core

def issquarefree(n): return core(n) == n

def a285734(n):

if n==1: return 0

j=int(n/2)

while True:

if issquarefree(j) and issquarefree(n - j): return j

else: j-=1

def a285735(n): return n - a285734(n)

def a286105(n): return 0 if n==1 else 1 + max(a286105(a285734(n)), a286105(a285735(n)))

def a286106(n): return 0 if n==1 else a286105(a285735(n)) - a286105(a285734(n))

def a286107(n): return 0 if n==1 else a285735(n) if a286106(n)>0 else a285734(n)

print [a286107(n) for n in xrange(1, 121)] # Indranil Ghosh, May 02 2017

STATUS

proposed

editing

#9 by Antti Karttunen at Tue May 02 14:33:05 EDT 2017

STATUS

editing

proposed

#8 by Antti Karttunen at Tue May 02 14:31:39 EDT 2017

CROSSREFS

Cf. A005117, A285734, A285735, A286103, A286104, A286105, A286106.