A071412 A002487 mod 3.

0, 1, 1, 2, 1, 0, 2, 0, 1, 1, 0, 2, 2, 2, 0, 1, 1, 2, 1, 1, 0, 2, 2, 1, 2, 1, 2, 2, 0, 1, 1, 2, 1, 0, 2, 0, 1, 2, 1, 1, 0, 2, 2, 1, 2, 0, 1, 0, 2, 0, 1, 0, 2, 1, 2, 2, 0, 1, 1, 2, 1, 0, 2, 0, 1, 1, 0, 2, 2, 2, 0, 1, 1, 0, 2, 0, 1, 2, 1, 1, 0, 2, 2, 1, 2, 0, 1, 0, 2, 2, 0, 1, 1, 1, 0, 2, 2, 2, 0, 1, 1, 1, 0, 2, 2

Offset

0,4

References

E. Dijkstra, Selected Writings on Computing, Springer, 1982, p. 232 (sequence is called fusc).

Links

Table of n, a(n) for n=0..104.

E. W. Dijkstra, An exercise for Dr. R. M. Burstall

E. W. Dijkstra, More about the function ``fusc''

Prog

(Python)
from functools import reduce
def A071412(n): return sum(reduce(lambda x, y:(x[0], (x[0]+x[1])%3) if int(y) else ((x[0]+x[1])%3, x[1]), bin(n)[-1:2:-1], (1, 0)))%3 if n else 0 # Chai Wah Wu, May 18 2023

Crossrefs

Sequence in context: A137696 A275731 A143614 * A080884 A354452 A362450

Adjacent sequences: A071409 A071410 A071411 * A071413 A071414 A071415

Keyword

nonn

Author

N. J. A. Sloane, Jul 15 2002

Status

approved