A189674 Partial sums of A189673.

0, 1, 1, 2, 3, 3, 3, 4, 4, 5, 6, 6, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 12, 12, 12, 13, 13, 14, 15, 15, 16, 17, 17, 17, 18, 18, 19, 20, 20, 21, 22, 22, 22, 23, 23, 23, 24, 24, 25, 26, 26, 26, 27, 27, 27, 28, 28, 29, 30, 30, 30, 31, 31, 32, 33, 33, 34, 35, 35, 35, 36, 36, 36, 37, 37, 38, 39, 39, 39, 40, 40

Offset

1,4

Comments

See A189673.

Links

Table of n, a(n) for n=1..81.

Kevin Ryde, Iterations of the Terdragon Curve, see index "TurnsL", with a(n) = TurnsL(n-1).

Formula

a(n) = a(floor((n+2)/3)) + floor((n+1)/3), where a(1)=0.

Mathematica

(See A189673.)

Prog

(PARI) a(n) = n--; (n + vecsum(digits(n, 3)%2))/2; \\ Kevin Ryde, Apr 23 2021

Crossrefs

Cf. A189673.

Sequence in context: A296021 A267097 A194198 * A156250 A029108 A350812

Adjacent sequences: A189671 A189672 A189673 * A189675 A189676 A189677

Keyword

nonn

Author

Clark Kimberling, Apr 25 2011

Status

approved