A202341 Numbers occurring exactly once in Hofstadter H-sequence A005374.

0, 2, 3, 6, 8, 9, 11, 12, 15, 16, 19, 21, 22, 25, 27, 28, 30, 31, 34, 36, 37, 39, 40, 43, 44, 47, 49, 50, 52, 53, 56, 57, 60, 62, 63, 66, 68, 69, 71, 72, 75, 76, 79, 81, 82, 85, 87, 88, 90, 91, 94, 96, 97, 99, 100, 103, 104, 107, 109, 110, 113, 115, 116, 118

Offset: 1

Author

Reinhard Zumkeller, Dec 17 2011

Keywords

• nonn

Comments

A202340(a(n)) = 1.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..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, A202340, A202342 (complement).

Programs

Haskell

import Data.List (elemIndices)
a202341 n = a202341_list !! (n-1)
a202341_list = elemIndices 1 a202340_list