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A165333 Numbers that eventually reach the fixed point 370 under "x -> sum of cubes of digits of x" (see A055012). 6

%I #9 Apr 14 2020 15:41:35

%S 7,19,34,37,43,58,67,70,73,76,85,88,91,109,118,124,139,142,145,148,

%T 154,157,166,169,175,178,181,184,187,190,193,196,214,223,226,232,241,

%U 247,259,262,268,274,277,286,295,304,307,319,322,334,340,343,346,355,358

%N Numbers that eventually reach the fixed point 370 under "x -> sum of cubes of digits of x" (see A055012).

%C A165330(a(n)) = 370;

%C Subsequence of A031179 and of A016777; a(n) mod 3 = 1.

%e a(3)=34: 34 -> 3^3+4^3=91 -> 9^3+1=730 -> 7^3+3^3+0=370.

%t f[n_] := Plus@@(IntegerDigits[n]^3); Trajectory[n_] := Most[NestWhileList[f, n, UnsameQ ,All]]; Select[Range[358], Last[Trajectory[#]] == 370&] (* _Ant King_, May 24 2013 *)

%Y Cf. A031179, A046197, A035504, A008585, A165334, A165335.

%K base,nonn

%O 1,1

%A _Reinhard Zumkeller_, Sep 17 2009

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Last modified May 13 07:22 EDT 2024. Contains 372498 sequences. (Running on oeis4.)