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A144766 Terms in A144719 that are themselves decimal palindromes. 1
121, 10001, 10201, 36763, 1226221, 7673767, 12467976421, 1030507050301, 1120237320211, 1225559555221, 1234469644321, 1334459544331, 100330272033001, 100827848728001, 101222252222101, 103023070320301, 121363494363121, 134312696213431, 10022212521222001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Presumed infinite, but it is difficult to find more terms.

The earlier claim that this sequence is a subsequence of A046450 was incorrect, as the counterexample of 7673767 =97*79111 shows. The reason is that A046450 checks only concatenations in the natural order of the prime factors, but this sequence here allows for both orders, 97//79111 as well as 79111//97, to be palindromic. - R. J. Mathar, Jan 22 2009

3*10^14 < a(19) <= 10022212521222001. - Donovan Johnson, Dec 08 2010

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..41

FORMULA

Subsequence of (A144719 INTERSECT A046328). - R. J. Mathar, Jan 22 2009

EXAMPLE

10001 = 73 * 137; 73137 is a palindrome.

CROSSREFS

Cf. A002113, A046450, A144719.

Sequence in context: A018849 A011814 A238320 * A277946 A263610 A176923

Adjacent sequences:  A144763 A144764 A144765 * A144767 A144768 A144769

KEYWORD

base,hard,nonn

AUTHOR

Reikku Kulon, Sep 20 2008

EXTENSIONS

a(7)-a(18) from Donovan Johnson, Dec 08 2010

a(19) from Giovanni Resta, Aug 31 2018

STATUS

approved

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Last modified May 10 21:08 EDT 2021. Contains 343780 sequences. (Running on oeis4.)