A215256 Longest palindromic factor of (n base 2); in case of tie choose largest; if it begins with 0 complement it.

1, 1, 1, 11, 11, 101, 11, 111, 111, 1001, 101, 101, 11, 101, 111, 1111, 1111, 10001, 1001, 1001, 101, 10101, 1001, 111, 111, 1001, 101, 11011, 111, 111, 1111, 11111, 11111, 100001, 10001, 10001, 11011, 1001, 1001, 1001, 101, 1001, 10101, 10101, 1001, 101101

Offset

0,4

Comments

The "if it begins with 0 complement it" clause is required because nonzero terms in the OEIS may not begin with 0.

Links

Lars Blomberg, Table of n, a(n) for n = 0..9999

Example

n=10 = 1010, longest palindromic factor is 101.
n=12 = 1100, there are two palindromic factors of length 2, namely 11 and 00, and we choose the larger, 11.
n=24 = 11000, longest palindromic factor is 000, complementing gives 111.

Crossrefs

Cf. A050430, A215467.

Sequence in context: A241870 A243127 A088761 * A265526 A265559 A265543

Adjacent sequences: A215253 A215254 A215255 * A215257 A215258 A215259

Keyword

nonn,base

Author

N. J. A. Sloane, Aug 15 2012

Extensions

More terms from Lars Blomberg, Jun 29 2014

Status

approved