login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A184392 a(n) is the product of palindromic divisors of n. 2
1, 2, 3, 8, 5, 36, 7, 64, 27, 10, 11, 144, 1, 14, 15, 64, 1, 324, 1, 40, 21, 484, 1, 1152, 5, 2, 27, 56, 1, 180, 1, 64, 1089, 2, 35, 1296, 1, 2, 3, 320, 1, 252, 1, 85184, 135, 2, 1, 1152, 7, 10, 3, 8, 1, 324, 3025, 448, 3, 2, 1, 720, 1, 2, 189, 64, 5, 18974736, 1, 8, 3, 70, 1, 10368, 1, 2, 15, 8, 5929, 36, 1, 320, 27, 2, 1, 1008, 5, 2, 3, 59969536, 1, 1620, 7, 8, 3, 2, 5, 1152, 1, 14, 970299, 40 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = A007955(n) / A179937(n).
EXAMPLE
For n = 20, set of palindromic divisors is {1, 2, 4, 5}; a(12) = 1*2*4*5 = 40.
MATHEMATICA
palQ[n_]:=Module[{idn=IntegerDigits[n]}, idn==Reverse[idn]]; f[n_]:=Times@@Select[Divisors[n], palQ]; Table[f[n], {n, 100}] (* Harvey P. Dale, Jan 21 2011 *)
PROG
(Python)
def ispal(n):
return n==int(str(n)[::-1])
def A184392(n):
s=1
for i in range(1, n+1):
if n%i==0 and ispal(i):
s*=i
return s # Indranil Ghosh, Feb 10 2017
CROSSREFS
Sequence in context: A091136 A140651 A190997 * A007955 A324502 A170826
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Jan 12 2011
EXTENSIONS
More terms from Harvey P. Dale, Jan 21 2011
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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