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A225867 a(n) = max_{2<=k<=(n-2)/2} sum_{d>1: d|n+k, k|n+d}1. 7
3, 2, 2, 3, 4, 1, 3, 3, 4, 4, 3, 2, 4, 3, 4, 4, 6, 2, 3, 4, 4, 4, 4, 2, 5, 3, 3, 6, 6, 4, 4, 4, 6, 4, 4, 2, 4, 5, 6, 5, 8, 2, 3, 4, 4, 6, 4, 3, 6, 6, 4, 6, 8, 2, 5, 5, 6, 4, 4, 4, 6, 4, 6, 8, 9, 2, 4, 5, 4, 5, 6, 6, 8, 4, 4, 6, 8, 3, 4, 6, 6, 8, 6, 3, 5, 4, 8, 6, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET

6,1

LINKS

Peter J. C. Moses, Table of n, a(n) for n = 6..10005

MAPLE

A225867 := proc(n)

    local a, k, nd ;

    a := 0 ;

    for k from 2 to n/2-1 do

        nd := 0 ;

        for d in numtheory[divisors](n+k) minus {1} do

            if modp(n+d, k) = 0 then

                nd := nd+1;

            end if;

        end do:

        a := max(a, nd) ;

    end do:

    a ;

end proc: # R. J. Mathar, Jul 04 2013

MATHEMATICA

Table[Max[Map[Count[(n+Rest[Divisors[n+#]])/#, _Integer]&, Range[2, Floor[(n-2)/2]]]], {n, 6, 105}] (* Peter J. C. Moses, Jun 27 2013 *)

PROG

(PARI) a(n)=my(t); for(k=2, n\2-1, t=max(sumdiv(n+k, d, (n+d)%k==0 && d>1), t)); t \\ Charles R Greathouse IV, Nov 25 2014

CROSSREFS

Sequence in context: A115061 A217834 A227877 * A046822 A129001 A029246

Adjacent sequences:  A225864 A225865 A225866 * A225868 A225869 A225870

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, May 18 2013

EXTENSIONS

Extended from a(14) by Peter J. C. Moses, May 18 2013

STATUS

approved

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Last modified April 23 07:51 EDT 2019. Contains 322381 sequences. (Running on oeis4.)