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A048343 Total number of distinct palindromes of form 'n-digit number' x 'n-digit number_reversed' (n-digit number not palindromic). 3
0, 1, 3, 10, 19, 44, 86, 171, 308, 551, 920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..11.

P. De Geest, Palindromic Products of Non Palindromic Integers and their Reversals

EXAMPLE

E.g., 3 solutions for 3-digit numbers: 102 * 201 = 20502; 112 * 211 = 23632; 122 * 221 = 26962.

PROG

(Python)

def A048343(n):

....y, plist = 0, []

....for i in range(10**(n-1), 10**n):

........s1 = str(i)

........s2 = s1[::-1]

........if s1 != s2:

............p = i*int(s2)

............if not p in plist:

................sp = str(p)

................if sp == sp[::-1]:

....................plist.append(p)

....................y += 1

....return y # Chai Wah Wu, Sep 05 2014

CROSSREFS

Cf. A048344.

Sequence in context: A160002 A294421 A027177 * A056789 A174476 A098645

Adjacent sequences:  A048340 A048341 A048342 * A048344 A048345 A048346

KEYWORD

nonn,base,more

AUTHOR

Patrick De Geest, Feb 15 1999

EXTENSIONS

More terms from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 18 2006

Offset changed and two terms added by Lars Blomberg, Nov 25 2011

STATUS

approved

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Last modified May 19 14:48 EDT 2019. Contains 323395 sequences. (Running on oeis4.)