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A039637 Number of steps to fixed point of "n -> n/2 or (n+1)/2 until result is prime". 1
1, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 3, 1, 2, 4, 4, 1, 3, 1, 3, 2, 2, 1, 4, 2, 2, 3, 3, 1, 5, 1, 5, 2, 2, 4, 4, 1, 2, 4, 4, 1, 3, 1, 3, 2, 2, 1, 5, 3, 3, 3, 3, 1, 4, 4, 4, 2, 2, 1, 6, 1, 2, 6, 6, 3, 3, 1, 3, 5, 5, 1, 5, 1, 2, 3, 3, 5, 5, 1, 5, 2, 2, 1, 4, 2, 2, 4, 4, 1, 3, 3, 3, 2, 2, 6, 6, 1, 4, 4, 4, 1, 4 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

MATHEMATICA

upplist[ n_Integer ] := Length/@Drop[ FixedPointList[ If[ EvenQ[ # ]&&#>2, #/ 2, If[ PrimeQ[ # ]||(#===1), #, (#+1)/2 ] ]&, n, 20 ], -1 ]

CROSSREFS

Cf. A039634-A039645.

Sequence in context: A008481 A127669 A056692 * A194548 A069157 A076526

Adjacent sequences:  A039634 A039635 A039636 * A039638 A039639 A039640

KEYWORD

nonn

AUTHOR

Wouter Meeussen (wouter.meeussen(AT)pandora.be)

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Last modified February 15 08:20 EST 2012. Contains 205729 sequences.