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A179627 a(n) = length of Collatz sequence starting with n-th prime 1
2, 6, 5, 12, 11, 8, 10, 15, 12, 14, 68, 16, 70, 21, 67, 10, 23, 15, 20, 66, 74, 25, 71, 22, 76, 19, 57, 65, 73, 11, 32, 21, 59, 29, 18, 13, 26, 18, 45, 23, 23, 15, 31, 77, 20, 77, 28, 47, 12, 25, 55, 36, 17, 44, 79, 52, 22, 30, 14, 30, 41, 76, 27, 57, 84, 27, 19, 73, 81, 24, 81 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Collatz Problem
FORMULA
a(n) = A006666(A000040(n)) + 1. [Reinhard Zumkeller, Apr 03 2012]
EXAMPLE
For n=4 the a(n)=12 because the fourth prime is 7 and if you start with 7, the 12th term of syracuse-sequence is 1. The syracuse-sequence starting with 7 has the dimension 12.
PROG
(Haskell)
a179627 = (+ 1) . a006666 . a000040 -- Reinhard Zumkeller, Apr 03 2012
CROSSREFS
Sequence in context: A077174 A211201 A359035 * A193977 A092313 A318358
KEYWORD
nonn
AUTHOR
Roland Schroeder (florola(AT)gmx.de), Jul 21 2010
EXTENSIONS
Offset fixed by Reinhard Zumkeller, Apr 03 2012
STATUS
approved

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Last modified July 24 20:30 EDT 2024. Contains 374585 sequences. (Running on oeis4.)