A249032 First differences of A075326.

3, 6, 4, 5, 5, 6, 4, 6, 4, 6, 4, 5, 5, 6, 4, 5, 5, 6, 4, 5, 5, 6, 4, 6, 4, 6, 4, 5, 5, 6, 4, 6, 4, 6, 4, 5, 5, 6, 4, 6, 4, 6, 4, 5, 5, 6, 4, 5, 5, 6, 4, 5, 5, 6, 4, 6, 4, 6, 4, 5, 5, 6, 4, 5, 5, 6, 4, 5, 5, 6, 4, 6, 4, 6, 4, 5, 5, 6, 4, 5, 5, 6, 4, 5, 5, 6

Offset

0,1

Comments

Can be constructed as follows. Apart from the initial "3", one always has either "6-4" (i.e., a 6 followed by a 4), or else "5-5". The 6-4's always come either alone (6-4) or triply (6-4, 6-4, 6-4), while the 5-5's always come alone. So if we let "6-4, 5-5" be represented by the numeral "1", and "6-4, 6-4, 6-4, 5-5" by the numeral "3", then the sequence of first differences, in this compressed code, is A080426, which itself is defined by a simple substitution rule. - D. R. Hofstadter, Oct 23 2014

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

D. R. Hofstadter, Anti-Fibonacci numbers, Oct 23 2014

Thomas Zaslavsky, Anti-Fibonacci Numbers: A Formula, Sep 26 2016

Prog

(Haskell)
a249032 n = a249032_list !! n
a249032_list = zipWith (-) (tail a075326_list) a075326_list
-- Reinhard Zumkeller, Oct 26 2014
(Python)
def A249032(n): return 4+int((n+1|(~((m:=n>>1)+1)&m).bit_length())&1^1)+int((n|(~((k:=n-1>>1)+1)&k).bit_length())&1) if n else 3 # Chai Wah Wu, Sep 11 2024

Crossrefs

Cf. A075326, A080426, A249031.

Sequence in context: A023676 A318524 A155530 * A251534 A364665 A073233

Adjacent sequences: A249029 A249030 A249031 * A249033 A249034 A249035

Keyword

nonn

Author

N. J. A. Sloane, Oct 26 2014

Status

approved