A320303 a(n)/2^n is the expected value of the length of the longest palindromic suffix of a random length-n binary string.

2, 6, 18, 44, 108, 242, 544, 1160, 2484, 5158, 10740, 21954, 44958, 91080, 184700, 372164, 750312, 1507080, 3028020, 6070856, 12173290, 24380120, 48831270, 97737536, 195633046, 391432098, 783212312, 1566788842, 3134338546, 6269470370, 12540592310, 25082901244, 50169366086

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Example

For n = 3, the strings 000, 010, 101, 111 have longest palindromic suffix of length 3; 001, 110 have longest palindromic suffix of length 1, and 011, 100 have longest palindromic suffix of length 2.  So a(3) = 4*3 + 2*1 + 2*2 = 18.

Crossrefs

Sequence in context: A272934 A192708 A233531 * A319415 A230137 A120414

Adjacent sequences: A320300 A320301 A320302 * A320304 A320305 A320306

Keyword

nonn

Author

Jeffrey Shallit, Oct 10 2018

Extensions

a(21)-a(33) from Giovanni Resta, Oct 10 2018

Status

approved