A202340 Number of times n occurs in Hofstadter H-sequence A005374.

1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1

Offset: 0

Author

Reinhard Zumkeller, Dec 17 2011

Keywords

• nonn

Comments

a(A202341(n)) = 1; a(A202342(n)) = 2.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
• Jeffrey Shallit, The Narayana Morphism and Related Words, arXiv:2503.01026 [math.CO], 2025.
• Eric Weisstein's World of Mathematics, Hofstadter H-Sequence.
• Wikipedia, Hofstadter sequence.
• Index entries for Hofstadter-type sequences.

Crossrefs

Cf. A005374, A136495, A202341, A202342.

Programs

Haskell

import Data.List (group)
a202340 n = a202340_list !! n
a202340_list = map length $ group a005374_list

Formula

a(n) = A136495(n+1) - A136495(n) for n > 0. - Alan Michael Gómez Calderón, Dec 23 2024