A307095 - OEIS

A307095

Let K_n = prefix of length n of Kolakoski sequence A000002; a(n) is the length of the longest palindromic suffix of K_n.

1, 1, 2, 4, 2, 4, 3, 3, 2, 4, 6, 5, 7, 2, 4, 3, 5, 7, 9, 11, 13, 3, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 6, 3, 2, 4, 6, 5, 7, 2, 4, 3, 3, 2, 4, 6, 8, 10, 12, 6, 5, 7, 2, 4, 3, 5, 7, 9, 11, 13, 3, 2, 4, 6, 5, 7, 2, 4, 3, 5, 7, 6, 3, 2, 4, 6, 8, 10, 12, 2, 4

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, PARI program for A307095

FORMULA

a(n+1) <= a(n) + 2.

EXAMPLE

The first terms, alongside K_n with longest palindromic suffix in parentheses, are:

n a(n) K_n

-- ---- ------------------

1 1 (1)

2 1 1(2)

3 2 1(22)

4 4 (1221)

5 2 122(11)

6 4 12(2112)

7 3 1221(121)

8 3 12211(212)

9 2 1221121(22)

10 4 122112(1221)

11 6 12211(212212)

12 5 1221121(22122)

13 7 122112(1221221)

14 2 122112122122(11)

15 4 12211212212(2112)

16 3 1221121221221(121)

PROG

(PARI) See Links section.

CROSSREFS

See A220080 for a similar sequence.

Cf. A000002.

Sequence in context: A280638 A333725 A163894 * A032059 A074075 A184186

Adjacent sequences: A307092 A307093 A307094 * A307096 A307097 A307098

KEYWORD

nonn

AUTHOR

Rémy Sigrist, Jun 04 2019

STATUS

approved