The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A086358 Digital root of n!. 3
 1, 1, 2, 6, 6, 3, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(n) = 9 for n >= 6. LINKS Index entries for linear recurrences with constant coefficients, signature (1). FORMULA a(n) = A010888(n!) = fixed-point of A007953(n!). It equals n! modulo(9); at r = 0 use 9. G.f.: (1 + x^2 + 4*x^3 - 3*x^5 + 6*x^6)/(1 - x). - Stefano Spezia, Jan 26 2023 EXAMPLE n = 5, 5 != 120, iteration list = {120,3}, a(5) = 3. MATHEMATICA sud[x_] := Apply[Plus, DeleteCases[IntegerDigits[x], 0]]; Table[FixedPoint[sud, w!], {w, 1, 87}] CROSSREFS Cf. A000142, A086353-A086361, A007953, A010888, A038194, A029898, A004152. Sequence in context: A153845 A105815 A136696 * A004152 A071678 A316164 Adjacent sequences: A086355 A086356 A086357 * A086359 A086360 A086361 KEYWORD nonn,base,easy,changed AUTHOR Labos Elemer, Jul 21 2003 EXTENSIONS a(0) = 1 prepended by Alois P. Heinz, Dec 05 2018 STATUS approved

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

Last modified January 27 10:15 EST 2023. Contains 359838 sequences. (Running on oeis4.)