This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A108514 If n is a power of 2, a(n)=n; otherwise a(n) = (p-1)*n/p where p = smallest odd prime divisor of n. 4
 1, 2, 2, 4, 4, 4, 6, 8, 6, 8, 10, 8, 12, 12, 10, 16, 16, 12, 18, 16, 14, 20, 22, 16, 20, 24, 18, 24, 28, 20, 30, 32, 22, 32, 28, 24, 36, 36, 26, 32, 40, 28, 42, 40, 30, 44, 46, 32, 42, 40, 34, 48, 52, 36, 44, 48, 38, 56, 58, 40, 60, 60, 42, 64, 52, 44, 66, 64, 46, 56, 70, 48, 72, 72, 50 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS David A. Corneth, Table of n, a(n) for n = 1..10000 Z. Nedev, A Reduced Computational Complexity Strategy for the Magnus-Derek Game, International Mathematical Forum, Vol. 9, 2014, no. 7, pp. 325 - 333. See p. 326. Z. Nedev and S. Muthukrishnan, The Nagger-Mover Game, DIMACS Tech. Report 2005-22. MAPLE with(numtheory): a:=proc(n) local nn: nn:=factorset(n): if n=1 then 1 elif nn={2} then n elif nn[1]=2 then (nn[2]-1)*n/nn[2] else (nn[1]-1)*n/nn[1] fi end: MATHEMATICA Array[If[IntegerQ@ Log2@ #1, #1, #1 (#2 - 1)/#2] & @@ {#, SelectFirst[FactorInteger[#][[All, 1]], # > 2 &]} &, 75] (* Michael De Vlieger, Oct 25 2017 *) PROG (PARI) first(n) = {my(res = vector(n, i, i)); forprime(p = 3, n, for(k = 1, n\p, if(res[k*p] == k*p, res[k*p]*=(p-1)/p))); res} \\ David A. Corneth, Oct 25 2017 CROSSREFS Cf. A108738. Sequence in context: A035114 A202103 A062570 * A120456 A115383 A219156 Adjacent sequences:  A108511 A108512 A108513 * A108515 A108516 A108517 KEYWORD nonn AUTHOR S. Muthukrishnan (muthu(AT)research.att.com), Jun 23 2005 EXTENSIONS Definition revised by N. J. A. Sloane, Oct 28 2017 at the suggestion of Michel Marcus. 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 22 14:07 EDT 2018. Contains 301071 sequences. (Running on oeis4.)