A218161 Recurring digital invariants of order 3.

55, 136, 160, 919

Offset

1,1

Links

Table of n, a(n) for n=1..4.

Eric Weisstein's World of Mathematics, Recurring Digital Invariant

Example

136: 1^3 + 3^3 + 6^3 = 244
244: 2^3 + 4^3 + 4^3 = 136,
so 136 is an order 3 recurring digital invariant.

Mathematica

lst = {}; f[n_] := Total[IntegerDigits[n]^3]; Do[a = n; Do[a = f[a]; If[a < n, Break[]]; If[a == n && ! n == f[n], AppendTo[lst, n]; Break[]], {3}], {n, 10^3}]; lst

Crossrefs

Cf. A218246-A218248.

Sequence in context: A063324 A046156 A224459 * A044306 A044687 A250578

Adjacent sequences: A218158 A218159 A218160 * A218162 A218163 A218164

Keyword

base,fini,full,nonn

Author

Arkadiusz Wesolowski, Oct 22 2012

Status

approved