A071939 a(n) = Max { sigma(k) : k = 1, 2, 3, ..., n } - Max { Phi(k) : k = 1, 2, 3, ..., n }.
0, 2, 2, 5, 3, 8, 6, 9, 9, 12, 8, 18, 16, 16, 16, 19, 15, 23, 21, 24, 24, 24, 20, 38, 38, 38, 38, 38, 32, 44, 42, 42, 42, 42, 42, 61, 55, 55, 55, 55, 51, 56, 54, 54, 54, 54, 50, 78, 78, 78, 78, 78, 72, 72, 72, 72, 72, 72, 66, 110, 108, 108, 108, 108, 108, 108, 102, 102, 102
Offset: 1
Programs
-
Mathematica
nn=70;With[{sig=DivisorSigma[1,Range[nn]],phi=EulerPhi[Range[ nn]]}, Table[ Max[Take[sig,n]]-Max[Take[phi,n]],{n,nn}]] (* Harvey P. Dale, May 06 2012 *) -
PARI
for(n=1,100,v=vector(n,x, sigma(x)); w=vector(n,y,eulerphi(y)); print1(vecmax(v)-vecmax(w),","))
Comments