A035504 Numbers that eventually reach 1 under "x -> sum of cubes of digits of x".

1, 10, 100, 112, 121, 211, 778, 787, 877, 1000, 1012, 1021, 1102, 1120, 1189, 1198, 1201, 1210, 1234, 1243, 1324, 1342, 1423, 1432, 1579, 1597, 1759, 1795, 1819, 1891, 1918, 1957, 1975, 1981, 2011, 2101, 2110, 2134, 2143, 2314, 2341, 2413, 2431, 2779

Offset

1,2

Comments

Subsequence of A016777; a(n) mod 3 = 1; A165330(a(n))=1. [Reinhard Zumkeller, Sep 17 2009]

References

R. K. Guy, Unsolved Problems Number Theory, Sect. E34.

Links

R. Zumkeller, Table of n, a(n) for n = 1..1000

R. Styer, Smallest Examples of Strings of Consecutive Happy Numbers, J. Int. Seq. 13 (2010), 10.6.3, Section 4.

Mathematica

f[n_]:=Plus@@(IntegerDigits[n]^3); Trajectory[n_] := Most[NestWhileList[f, n, UnsameQ, All]]; Select[Range[2780], Last[Trajectory[#]]==1 &] (* Ant King, May 24 2013 *)

Crossrefs

Cf. A007770.

Cf. A046197, A008585, A165333, A165334, A165335; subsequence of A031179.

Sequence in context: A276349 A167502 A135652 * A072366 A349316 A119082

Adjacent sequences: A035501 A035502 A035503 * A035505 A035506 A035507

Keyword

nonn,easy,base

Author

N. J. A. Sloane.

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Mar 31 2000

Status

approved