A039643 - OEIS

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A039643

Number of steps to fixed point of "k -> k/2 or (k-1)/2 until result is prime", starting with prime(n)+1.

4

1, 2, 2, 3, 3, 2, 4, 3, 4, 3, 5, 2, 4, 3, 5, 3, 4, 2, 3, 6, 2, 5, 5, 4, 6, 6, 4, 4, 4, 5, 7, 7, 4, 4, 3, 4, 2, 3, 6, 3, 5, 5, 7, 2, 7, 7, 3, 6, 6, 6, 4, 6, 6, 4, 8, 8, 3, 5, 2, 5, 3, 3, 5, 5, 2, 3, 3, 7, 4, 4, 6, 6, 5, 5, 4, 8, 3, 2, 8, 8, 6, 2, 6, 6, 6, 6, 7, 2, 7, 5, 5, 7, 4, 4, 5, 5, 3, 9, 3, 2, 3, 3

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OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MATHEMATICA

PROG

(Haskell)

a039643 n = snd $ until ((== 1) . a010051 . fst)

(\(x, i) -> (x `div` 2 , i + 1)) (a000040 n + 1, 1)

-- Reinhard Zumkeller, Nov 17 2013

CROSSREFS

Cf. A039634-A039645.

Cf. A010051, A000040, A039639, A039645, A039636.

Sequence in context: A214749 A239330 A276273 * A288887 A154258 A253900

Adjacent sequences: A039640 A039641 A039642 * A039644 A039645 A039646

KEYWORD

nonn

AUTHOR

Wouter Meeussen

EXTENSIONS

Offset corrected by Reinhard Zumkeller, Nov 17 2013

STATUS

approved