

A175240


Call any positive integer that is a palindrome when written in binary a "binary palindrome". a(n) = the smallest binary palindrome such that a(n)*(the nth binary palindrome) is not a binary palindrome.


1



27, 5, 5, 9, 5, 17, 5, 3, 5, 33, 3, 7, 5, 65, 9, 5, 3, 15, 3, 3, 5, 129, 3, 5, 3, 27, 3, 5, 5, 257, 17, 5, 3, 5, 5, 3, 3, 27, 3, 3, 3, 5, 3, 3, 5, 513, 3, 9, 3, 5, 3, 3, 3, 27, 7, 3, 3, 5, 3, 5, 5, 1025, 33, 5, 3, 9, 5, 3, 3, 5, 5, 5, 3, 3, 3, 3, 3, 27, 3, 3, 5, 3, 3, 3, 3, 5, 3, 3, 3, 5, 3, 3, 5
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

2,1


COMMENTS

There are no palindromes that work for a(1), since the first positive binary palindrome is 1.
(The nth positive binary palindrome)*a(n) = A175241(n), a nonpalindrome when written in binary.


LINKS

Table of n, a(n) for n=2..94.


EXAMPLE

The 6th positive integer that is a palindrome when written in binary is 15, which is 1111 in binary. Checking the binary palindromes multiplied by 15: 1*15 = 15, which is 1111 in binary, a palindrome. 3, 11 in binary, is the second positive binary palindrome. 3*15 = 45, which is 101101 in binary, a palindrome. 5, 101 in binary, is the 3rd positive binary palindrome. 5*15 = 75, which is 1001011 in binary, not a palindrome. Since 5*15 is not a palindrome in binary, then a(6) (the 5th term of the sequence) is 5.


CROSSREFS

Cf. A006995, A175241.
Sequence in context: A040712 A040714 A040711 * A204877 A040709 A218014
Adjacent sequences: A175237 A175238 A175239 * A175241 A175242 A175243


KEYWORD

base,nonn


AUTHOR

Leroy Quet, Mar 11 2010


EXTENSIONS

Extended by Ray Chandler, Mar 13 2010


STATUS

approved



