A165335 - OEIS

A165335

Numbers that eventually reach the fixed point 407 under "x -> sum of cubes of digits of x" (see A055012).

47, 74, 77, 89, 98, 407, 449, 470, 494, 578, 587, 668, 686, 704, 707, 740, 758, 770, 785, 788, 809, 857, 866, 875, 878, 887, 890, 908, 944, 980, 1124, 1139, 1142, 1148, 1157, 1175, 1178, 1184, 1187, 1193, 1214, 1241, 1319, 1367, 1376, 1391, 1412, 1418, 1421

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OFFSET

1,1

COMMENTS

A165330(a(n)) = 407.

LINKS

Table of n, a(n) for n=1..49.

FORMULA

Complement of A165334 with respect to A016789; a(n) mod 3 = 2.

EXAMPLE

a(4)=89: 89 -> 8^3+9^3=1241 -> 1+2^3+4^3+1=74 -> 7^3+4^3=407.

MATHEMATICA

f[n_] := Plus@@(IntegerDigits[n]^3); Trajectory[n_] := Most[NestWhileList[f, n, UnsameQ, All]]; Select[Range[1421], Last[Trajectory[#]]==407 &] (* Ant King, May 24 2013 *)

Select[Range[1500], FixedPoint[Total[IntegerDigits[#]^3]&, #, 100]==407&] (* Harvey P. Dale, Apr 17 2020 *)

CROSSREFS

Subsequence of A031179.

Cf. A046197, A035504, A008585, A165333.

Sequence in context: A052231 A092178 A338273 * A039425 A043248 A044028

Adjacent sequences: A165332 A165333 A165334 * A165336 A165337 A165338

KEYWORD

base,nonn

AUTHOR

Reinhard Zumkeller, Sep 17 2009

STATUS

approved