

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
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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



