

A123390


Triangle read by rows: nth row starts with n and continues with half the previous value as long as that is even.


2



1, 2, 1, 3, 4, 2, 1, 5, 6, 3, 7, 8, 4, 2, 1, 9, 10, 5, 11, 12, 6, 3, 13, 14, 7, 15, 16, 8, 4, 2, 1, 17, 18, 9, 19, 20, 10, 5, 21, 22, 11, 23, 24, 12, 6, 3, 25, 26, 13, 27, 28, 14, 7, 29, 30, 15, 31, 32, 16, 8, 4, 2, 1, 33, 34, 17, 35, 36, 18, 9, 37, 38, 19, 39, 40, 20, 10, 5, 41, 42, 21
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OFFSET

1,2


COMMENTS

A fractal sequence, generated by the rule a(n) is a new maximum when a(n1) is odd and a repetition of an earlier value when a(n1) is even.


LINKS

Alois P. Heinz, Rows n = 1..10000, flattened


FORMULA

a(1) = 1, for n > 1, if a(n1) is even, a(n) = a(n1)/2, otherwise a(n) = (max_{k<n} a(k)) + 1.
Ordinal transform of A082850.


EXAMPLE

Triangle starts
1;
2, 1;
3;
4, 2, 1;
5;
6, 3;
7;
8, 4, 2, 1;
9;
10, 5;
11;
12, 6, 3;
13;


MAPLE

T:= proc(n) local m, l; m:=n; l:= m;
while irem(m, 2, 'm')=0 do l:=l, m od: l
end:
seq(T(n), n=1..40); # Alois P. Heinz, Oct 09 2015


MATHEMATICA

Flatten[Function[n, NestWhile[Append[#, Last[#]/2] &, {n}, EvenQ[Last[#]] &]][#] & /@ Range[20]] (* Birkas Gyorgy, Apr 13 2011 *)


CROSSREFS

Row lengths are A001511. Cf. A120385.
Sequence in context: A273823 A112384 A248514 * A306806 A306805 A162598
Adjacent sequences: A123387 A123388 A123389 * A123391 A123392 A123393


KEYWORD

nonn,tabf


AUTHOR

Franklin T. AdamsWatters, Oct 13 2006


STATUS

approved



