A383143 Number of positive integers with a shortest addition-subtraction chain of length n.

1, 1, 2, 3, 5, 9, 16, 28, 49, 88, 156, 280, 499, 904, 1639, 2986, 5442, 9936, 18134

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Neill Clift, Addition Subtraction Chains.

Index to sequences related to the complexity of n

Formula

a(n) >= A003065(n).

Example

a(6) = 16 because the number of occurrences of 6 in A128998 is 16. These numbers are 19, 21, 22, 23, 25, 26, 27, 28, 30, 31, 33, 34, 36, 40, 48, 64.

Crossrefs

Cf. A003065, A128998, A383002, A383142.

Sequence in context: A079960 A005314 A099529 * A088352 A002572 A114834

Adjacent sequences: A383140 A383141 A383142 * A383144 A383145 A383146

Keyword

nonn,hard,more

Author

Jinyuan Wang, Apr 17 2025

Status

approved