A065386 Successive record values of the cototient function (A051953).

0, 1, 2, 4, 6, 8, 12, 16, 22, 24, 30, 32, 36, 44, 46, 48, 54, 60, 66, 70, 72, 78, 88, 90, 92, 94, 96, 110, 120, 132, 138, 140, 162, 176, 180, 184, 198, 210, 220, 250, 264, 270, 294, 324, 330, 342, 352, 360, 382, 396, 402, 426, 440, 486, 500, 514, 522, 528, 550, 588

Offset: 1

Author

Labos Elemer, Nov 05 2001

Keywords

• nonn

Examples

			a(8)=22 because for m = 1...29 the cototient values are all smaller than cototient(30)=22, where 30=A065385(8) and 22 is the 8th term in the sequence of such local records.
		

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Crossrefs

Cototient(A065385(n)).

A006093 gives similar records for the totient function. A002093, A002182, A015702, A005250 are analogous sequences for other functions.

a(n) = A051953(A065385(n)).

Cf. A051953, A065386, A000010.

Programs

Mathematica

a=0; s=0; Do[s = n-EulerPhi[n]; If[s>a, a=s; Print[s]], {n, 1, 10000}]
(* Second program: *)
With[{s = Array[# - EulerPhi@ # &, 10^3]}, Union@ FoldList[Max, s]] (* Michael De Vlieger, Nov 03 2017 *)

PARI

r=-1; for(n=1,1000,d=n-eulerphi(n); if(r
				

PARI

{ n=0; x=-1; for (m=1, 10^9, c=m - eulerphi(m); if (c > x, x=c; write("b065386.txt", n++, " ", c); if (n==1000, return)) ) } \\ Harry J. Smith, Oct 17 2009