A071622 a(n) = (-1)*Sum_{k=1..n} (-1)^floor((4/3)^k).

1, 2, 1, 2, 1, 2, 3, 4, 5, 6, 7, 8, 7, 6, 5, 6, 7, 8, 7, 8, 7, 6, 7, 6, 5, 6, 5, 6, 7, 8, 7, 6, 7, 8, 7, 6, 5, 6, 7, 8, 9, 10, 11, 12, 11, 10, 9, 10, 11, 10, 9, 8, 7, 8, 7, 8, 7, 8, 9, 10, 9, 8, 9, 8, 9, 8, 7, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 14, 15, 14, 13, 12, 13, 12, 13, 12, 11, 10, 9, 10, 9

Offset

1,2

Comments

Conjecture: for n>2300, a(n) > log(n)^2.

Links

Table of n, a(n) for n=1..91.

Mathematica

Table[(-1)Sum[(-1)^Floor[(4/3)^k], {k, n}], {n, 100}] (* Harvey P. Dale, Jul 27 2025 *)

Prog

(PARI) for(n=1, 100, print1(-sum(i=1, n, sign((-1)^floor((4/3)^i))), ", "))

Crossrefs

Cf. A071532.

Sequence in context: A139803 A058746 A080916 * A182063 A135990 A347256

Adjacent sequences: A071619 A071620 A071621 * A071623 A071624 A071625

Keyword

easy,nonn

Author

Benoit Cloitre, Jun 22 2002

Status

approved