

A160541


Number of oddtheneven runs to reach 1 under the modified `3x+1' map: n > n/2 if n is even, n > (3n+1)/2 if n is odd.


0



0, 1, 1, 1, 1, 2, 3, 1, 4, 2, 3, 2, 2, 4, 2, 1, 3, 5, 4, 2, 1, 4, 2, 2, 5, 3, 17, 4, 4, 3, 16, 1, 6, 4, 2, 5, 4, 5, 6, 2, 17, 2, 6, 4, 4, 3, 16, 2, 5, 6, 5, 3, 2, 18, 17, 4, 7, 5, 6, 3, 3, 17, 15, 1, 6, 7, 5, 4, 3, 3, 16, 5, 18, 5, 2, 5, 5, 7, 6, 2, 4, 18, 17, 2, 1, 7, 5, 4, 6, 5, 14, 3, 3, 17, 15, 2, 19
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OFFSET

1,6


COMMENTS

The 2>1 step is not counted.


LINKS

Table of n, a(n) for n=1..97.


EXAMPLE

7>11>17>26>13>20>10>5>8>4>2>1, so the oddtheneven runs are (7>11>17>26) (13>20>10) (5>8>4>2), and a(7) is 3.


MATHEMATICA

Table[Length[Split[Most[NestWhileList[T, i, #!=1&]], OddQ[ #1]EvenQ[ #2]]], {i, 1, 100}]


CROSSREFS

Sequence in context: A143361 A152547 A083906 * A286001 A304106 A022446
Adjacent sequences: A160538 A160539 A160540 * A160542 A160543 A160544


KEYWORD

nonn


AUTHOR

Brenton Bostick (bostick(AT)gmail.com), May 18 2009


STATUS

approved



