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A179937 a(n) is the product of the non-palindromic divisors of n. 2
1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 1, 12, 13, 14, 15, 16, 17, 18, 19, 200, 21, 1, 23, 288, 25, 338, 27, 392, 29, 4500, 31, 512, 1, 578, 35, 7776, 37, 722, 507, 8000, 41, 12348, 43, 1, 675, 1058, 47, 221184, 49, 12500, 867, 17576, 53, 26244, 1, 21952, 1083, 1682, 59 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,10
LINKS
FORMULA
a(n) = A007955(n) / A184392(n).
EXAMPLE
For n = 20, set of non-palindromic divisors is {10, 20}; a(12) = 10*20 = 200.
MATHEMATICA
Table[Times@@Select[Divisors[n], !PalindromeQ[#]&], {n, 60}] (* Harvey P. Dale, May 15 2023 *)
PROG
(Python)
def ispal(n):
return n==int(str(n)[::-1])
def A179937(n):
s=1
for i in range(1, n+1):
if n%i==0 and not ispal(i):
s*=i
return s # Indranil Ghosh, Feb 10 2017
CROSSREFS
Sequence in context: A070606 A332803 A073731 * A198487 A099613 A209924
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Jan 12 2011
EXTENSIONS
More terms from Indranil Ghosh, Feb 10 2017
STATUS
approved

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)