A083094 - OEIS

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A083094

Numbers k such that Sum_{j=0..k} (binomial(k,j) mod 3) is odd.

0, 8, 20, 24, 56, 60, 72, 80, 164, 168, 180, 188, 216, 224, 236, 240, 488, 492, 504, 512, 540, 548, 560, 564, 648, 656, 668, 672, 704, 708, 720, 728, 1460, 1464, 1476, 1484, 1512, 1520, 1532, 1536, 1620, 1628, 1640, 1644, 1676, 1680, 1692, 1700, 1944, 1952

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Apparently a(n)/2 (mod 3) = A010060(n), the Thue-Morse sequence.

LINKS

Table of n, a(n) for n=1..50.

PROG

(PARI) isok(n) = sum(k=0, n, binomial(n, k) % 3) % 2; \\ Michel Marcus, Dec 05 2013

CROSSREFS

Cf. A010060, A051638, A083093, A083095.

Sequence in context: A205318 A100212 A349168 * A164916 A207190 A110116