OFFSET
1,4
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..1000
FORMULA
MATHEMATICA
Module[{nn=70, eu, ds}, eu=Accumulate[EulerPhi[Range[nn]]]; ds=Accumulate[ DivisorSigma[ 0, Range[nn]]]; eu-ds] (* Harvey P. Dale, Oct 21 2017 *)
PROG
(PARI) j=[]; for(n=1, 200, a=sum(k=1, n, eulerphi(k)); b=sum(k=1, n, numdiv(k)); j=concat(j, a-b)); j
(PARI) { a=0; for (n=1, 1000, write("b063088.txt", n, " ", a+=eulerphi(n) - numdiv(n)) ) } \\ Harry J. Smith, Aug 17 2009
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Jason Earls, Aug 06 2001
STATUS
approved