A393435 a(n) = (-1)^A033264(n).

1, 1, -1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 1

Offset

0

Comments

A033264(n) is the number of occurrences of 10 in the binary expansion of n.

Links

Table of n, a(n) for n=0..102.

Patrick Morton and W. J. Mourant, Paper folding, digit patterns and groups of arithmetic fractals, Proceedings of the London Mathematical Society 3.2 (1989): 253-293. [The present sequence is the subject of Table 1]

Maple

a:= n-> (-1)^nops([StringTools[SearchAll]("01", cat("", Bits[Split](n)[]))]):
seq(a(n), n=0..102);  # Alois P. Heinz, Mar 07 2026

Mathematica

a[n_]:=(-1)^SequenceCount[IntegerDigits[n, 2], {1, 0}]; Array[a, 103, 0] (* Stefano Spezia, Mar 07 2026 *)

Crossrefs

Cf. A033264.

Sequence in context: A065357 A119665 A121241 * A122188 A158388 A162285

Adjacent sequences: A393432 A393433 A393434 * A393436 A393437 A393438

Keyword

sign,base

Author

N. J. A. Sloane, Mar 07 2026

Status

approved