

A004074


a(n) = 2*A004001(n)  n, where A004001 is the HofstadterConway $10000 sequence.


9



1, 0, 1, 0, 1, 2, 1, 0, 1, 2, 3, 2, 3, 2, 1, 0, 1, 2, 3, 4, 3, 4, 5, 4, 5, 4, 3, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 4, 5, 6, 7, 6, 7, 8, 7, 8, 7, 6, 7, 8, 7, 8, 7, 6, 7, 6, 5, 4, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 5, 6, 7, 8, 9, 8, 9, 10, 11, 10, 11, 12, 11, 12, 11, 10, 11, 12, 13, 12, 13, 14, 13, 14, 13, 12
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OFFSET

1,6


COMMENTS

The sequence is 0 at 2^n for n = 1, 2, 3, ... The maximum value between 2^n and 2^(n+1) appears to be A072100(n).  T. D. Noe, Jun 04 2012
Hofstadter shows the plot of sequence A004001(n)(n/2) at point 10:52 of the part two of DIMACS lecture. This sequence is obtained by doubling those values, thus producing only integers. Cf. also A249071.  Antti Karttunen, Oct 22 2014


LINKS

D. R. Hofstadter, Analogies and Sequences: Intertwined Patterns of Integers and Patterns of Thought Processes, Lecture in DIMACS Conference on Challenges of Identifying Integer Sequences, Rutgers University, October 10 2014; Part 1, Part 2.


FORMULA



MATHEMATICA

Clear[a]; a[1] = 1; a[2] = 1; a[n_] := a[n] = a[a[n  1]] + a[n  a[n  1]]; Table[2*a[n]  n, {n, 100}] (* T. D. Noe, Jun 04 2012 *)


PROG



CROSSREFS

Cf. also A249071 (gives the even bisection halved), A233270 (also has a similar Blancmange curve appearance).


KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



