A104594 A129760/2.

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

Offset: 1

Author

N. J. A. Sloane, May 25 2008

Keywords

• nonn

Comments

a(n) is the degree of the n-th Stern polynomial defined in Beck and Dilcher. - Michel Marcus, May 20 2022

Links

• George Beck and Karl Dilcher, A Matrix Related to Stern Polynomials and the Prouhet-Thue-Morse Sequence, arXiv:2106.10400 [math.CO], 2021.
• R. Brown and J. L. Merzel, The number of Ducci sequences with a given period, Fib. Quart., 45 (2007), 115-121.

Crossrefs

Cf. A129760.

Programs

Maple

a:= n-> Bits[And](n, n-1)/2:
seq(a(n), n=1..100);  # Alois P. Heinz, May 20 2022

PARI

a(n) = bitand(n, n-1)/2; \\ Michel Marcus, Sep 06 2017