A376638 a(n) is the number of n-digit numbers in A376637.

2, 4, 4, 6, 8, 4, 12, 8, 8, 12, 20, 0, 16, 16, 12, 24, 16, 8, 12, 16, 32, 12, 20, 32, 24, 16, 16, 12, 16, 20, 40, 40, 8, 28, 44, 20, 44, 28, 20, 24, 20, 20, 16, 32, 20, 44, 44, 56, 28, 28, 20, 60, 52, 24, 56, 56, 20, 36, 36, 32, 24, 24, 32, 24, 16, 60, 16, 32

Offset: 1

Author

Rémy Sigrist, Sep 30 2024

Keywords

• nonn

Comments

All terms are even: if a word w belongs to A376637, then replacing 1's by 2's and 2's by 1's in w yields another word in A376637.

a(n)/2 is the number of terms of A376637 with digital sum n.

Examples

			Sequence A376637 begins: 1, 2,  11, 12, 21, 22,  112, 122, 211, 221,  1121.
So a(1) = 2, a(2) = 4, a(3) = 4.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..8192
• Rémy Sigrist, C++ program
• Index entries for sequences related to Kolakoski sequence

Crossrefs

Cf. A007782, A376637.