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A243017 Least number k > 0 such that k*n/(k+n) and k*n/(k-n) are integers or 0 if no such k exists. 3
0, 0, 6, 12, 0, 3, 0, 24, 18, 15, 0, 4, 0, 0, 10, 48, 0, 9, 0, 30, 28, 0, 0, 8, 0, 0, 54, 21, 0, 15, 0, 96, 66, 0, 210, 12, 0, 0, 78, 24, 0, 21, 0, 132, 30, 0, 0, 16, 0, 75, 102, 156, 0, 27, 66, 42, 114, 0, 0, 12, 0, 0, 84, 192, 0, 33, 0, 204, 138, 105, 0, 24, 0, 0, 50, 228 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..76.

EXAMPLE

3*6/(6+3) = 2 and 3*6/(6-3) = 9 are both integers. Thus a(3) = 6.

PROG

(PARI) a(n)=for(k=1, n*(n+1), if(k!=n, if((k*n)%(k+n)==0&&(k*n)%(k-n)==0, return(k))))

n=1; while(n<100, print1(a(n), ", "); n+=1)

CROSSREFS

Sequence in context: A145746 A024267 A028584 * A084342 A243045 A242931

Adjacent sequences:  A243014 A243015 A243016 * A243018 A243019 A243020

KEYWORD

nonn

AUTHOR

Derek Orr, May 29 2014

STATUS

approved

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Last modified February 26 00:08 EST 2020. Contains 332270 sequences. (Running on oeis4.)