

A055510


Largest odd prime in sequence obtained in 3x+1 (or Collatz) problem starting at n, or 0 if no such prime is found.


1



0, 0, 5, 0, 5, 5, 17, 0, 17, 5, 17, 5, 13, 17, 53, 0, 17, 17, 29, 5, 0, 17, 53, 5, 29, 13, 1619, 17, 29, 53, 1619, 0, 29, 17, 53, 17, 37, 29, 101, 5, 1619, 0, 43, 17, 17, 53, 1619, 5, 37, 29, 29, 13, 53, 1619, 1619, 17, 43, 29, 101, 53, 61, 1619, 1619, 0, 37, 29, 101, 17, 13
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OFFSET

1,3


LINKS

Table of n, a(n) for n=1..69.
Index entries for sequences related to 3x+1 (or Collatz) problem
Eric Weisstein's World of Mathematics, Collatz Problem


MATHEMATICA

op[n_]:=Module[{lst=NestWhileList[If[EvenQ[#], #/2, 3#+1]&, n, #!=1&], m}, m= Max[Select[ lst, PrimeQ]]; If[m<3, 0, m]]; Array[op, 70] {* From Harvey P. Dale, Apr 30 2011 *)


CROSSREFS

Cf. A055509.
Sequence in context: A144702 A238192 A156716 * A200397 A265302 A228764
Adjacent sequences: A055507 A055508 A055509 * A055511 A055512 A055513


KEYWORD

nonn


AUTHOR

G. L. Honaker, Jr., Jun 30 2000


EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Aug 09 2001


STATUS

approved



