This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A113708 Limit set for operation of repeatedly replacing a number with the sum of the 4th power of its digits. 1
 0, 1, 1138, 1634, 2178, 4179, 4338, 4514, 6514, 6725, 8208, 9219, 9474, 13139 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The trajectories under the given map terminate either at one of the fixed points 0, 1, 1634, 8208, 9474, or by reaching a member of the 2-cycle 2178 -> 6514 or the 7-cycle 1138 -> 4179 -> 9219 -> 13139 -> 6725 -> 4338 -> 4514. Least k which returns a(n): 0, 1, 1138, 1346, 127, 8, 47, 3348, 66, 6725, 12, 1479, 4479, 2; and the number of iterations to get there are: 0, 0, 0, 1, 11, 3, 2, 1, 3, 0, 4, 1, 1, 18. - Robert G. Wilson v, Jan 24 2006 REFERENCES Boris A. Kordemsky, The Moscow Puzzles, p. 160 (1972) LINKS MATHEMATICA lst = {}; Do[a = NestWhile[Plus @@ (IntegerDigits@#^4)&, n, Unequal, All]; If[FreeQ[lst, a], AppendTo[lst, a]], {n, 6725}]; Union@lst (* Robert G. Wilson v, Jan 24 2006 *) CROSSREFS Cf. A046156. Sequence in context: A066365 A014365 A027545 * A206112 A232133 A261572 Adjacent sequences:  A113705 A113706 A113707 * A113709 A113710 A113711 KEYWORD base,full,nonn,fini AUTHOR Harvey P. Dale, Jan 17 2006 EXTENSIONS Erroneous comment regarding the trajectory terminating conditions corrected by Ant King Jun 04 2013 Zero added to the set of least k’s which return a(n) for consistency with the first term of the given limit set. Similarly for the number of iterations required to get there, and two of the existing terms were corrected - Ant King Jun 07 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 15 07:56 EDT 2019. Contains 328026 sequences. (Running on oeis4.)