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

Author

Clark Kimberling, Apr 25 2011

Keywords

• nonn

Comments

See A189673.

Links

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

Crossrefs

Cf. A189673.

Programs

Mathematica

(See A189673.)

PARI

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

Formula

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