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A332453 Starting from sigma(n), number of tripling steps to reach 1 in '3x+1' problem, or -1 if 1 is never reached. 5
0, 2, 0, 5, 2, 2, 0, 5, 2, 6, 2, 5, 5, 2, 2, 39, 6, 11, 1, 1, 0, 6, 2, 5, 39, 1, 1, 5, 5, 6, 0, 39, 2, 41, 2, 33, 6, 5, 5, 4, 1, 2, 4, 1, 11, 6, 2, 39, 10, 4, 6, 7, 41, 5, 6, 5, 1, 4, 5, 1, 39, 2, 2, 15, 1, 6, 3, 39, 2, 6, 6, 43, 6, 10, 39, 3, 2, 1, 1, 4, 34, 39, 1, 5, 41, 8, 5, 4, 4, 5, 5, 1, 0, 6, 5, 39, 7, 45, 11, 7, 7, 41, 2, 12, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..8192

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Index entries for sequences related to 3x+1 (or Collatz) problem

Index entries for sequences related to sigma(n)

FORMULA

a(n) = A006667(A000203(n)).

a(n) = A332209(n) - A332452(n).

PROG

(PARI)

A006667(n) = { my(t=0); while(n>1, if(n%2, t++; n=3*n+1, n>>=1)); (t); };

A332453(n) = A006667(sigma(n));

CROSSREFS

Cf. A000203, A006667, A332209, A332452, A332455.

Sequence in context: A075603 A264357 A221573 * A066283 A240663 A267213

Adjacent sequences:  A332450 A332451 A332452 * A332454 A332455 A332456

KEYWORD

nonn

AUTHOR

Antti Karttunen, Feb 16 2020

STATUS

approved

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Last modified October 26 02:14 EDT 2021. Contains 348256 sequences. (Running on oeis4.)