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

Author

N. J. A. Sloane, Jul 15 2002

Keywords

• nonn

References

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

Links

• E. W. Dijkstra, An exercise for Dr. R. M. Burstall
• E. W. Dijkstra, More about the function ``fusc''

Programs

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