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A003620 Number of iterations until 3n reaches 153 under x goes to sum of cubes of digits map.
(Formerly M2829)
1
3, 10, 4, 5, 10, 2, 5, 3, 2, 3, 6, 6, 6, 3, 5, 6, 10, 5, 5, 10, 6, 6, 6, 2, 5, 8, 2, 6, 8, 4, 6, 6, 4, 5, 10, 2, 4, 7, 11, 5, 7, 9, 10, 7, 1, 6, 7, 11, 7, 10, 0, 6, 8, 9, 6, 4, 11, 7, 13, 2, 6, 4, 4, 10, 8, 4, 5, 3, 2, 5, 7, 9, 10, 4, 8, 8, 7, 5, 10, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = A165331(A008585(n)). [From Reinhard Zumkeller, Nov 21 2009]

REFERENCES

J. Roberts, Lure of the Integers, Math. Assoc. America, 1992, p. 13.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..80.

MATHEMATICA

Table[Length[NestWhileList[Total[IntegerDigits[#]^3]&, 3n, #!=153&]]-1, {n, 80}] (* Harvey P. Dale, Dec 19 2011 *)

CROSSREFS

Cf. A055012. [From Reinhard Zumkeller, Nov 21 2009]

Sequence in context: A170855 A320583 A131814 * A235923 A192028 A111229

Adjacent sequences:  A003617 A003618 A003619 * A003621 A003622 A003623

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Mira Bernstein

STATUS

approved

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Last modified December 9 19:51 EST 2019. Contains 329879 sequences. (Running on oeis4.)