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Revision History for A087991 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Number of non-palindromic divisors of n.
(history; published version)
#26 by Joerg Arndt at Tue May 04 02:01:21 EDT 2021
STATUS

reviewed

approved

#25 by Michel Marcus at Mon May 03 11:26:37 EDT 2021
STATUS

proposed

reviewed

#24 by F. Chapoton at Mon May 03 11:18:02 EDT 2021
STATUS

editing

proposed

#23 by F. Chapoton at Mon May 03 11:17:56 EDT 2021
PROG

w=str(n)

return nw==int(str(n)w[::-1])

print([A087991(n) for n in range(1, 60)]) # Indranil Ghosh, Feb 10 2017

STATUS

reviewed

editing

Discussion
Mon May 03
11:18
F. Chapoton: ok, fixed now
#22 by Joerg Arndt at Mon May 03 01:30:47 EDT 2021
STATUS

proposed

reviewed

Discussion
Mon May 03
09:55
Michel Marcus: here too, one zero too many
#21 by Michel Marcus at Sun May 02 11:57:55 EDT 2021
STATUS

editing

proposed

#20 by Michel Marcus at Sun May 02 11:57:49 EDT 2021
FORMULA

a(n) = A000005[(n]) - A087990[(n]).

STATUS

proposed

editing

#19 by F. Chapoton at Sun May 02 11:44:39 EDT 2021
STATUS

editing

proposed

#18 by F. Chapoton at Sun May 02 11:44:31 EDT 2021
PROG

....if return n==int(str(n)[::-1]):return True

....return False

.... s = 0

.... for i in range(1, n+1):

........ if n%i==0 and not ispal(i)==False:

............ s+=1

return s

....return s print([A087991(n) for n in range(60)]) # Indranil Ghosh, Feb 10 2017

STATUS

approved

editing

Discussion
Sun May 02
11:44
F. Chapoton: adapt py code to py3
#17 by Bruno Berselli at Fri Feb 10 11:22:50 EST 2017
STATUS

proposed

approved