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A063846 Numbers k such that sigma(k) - usigma(k) > 2k. 5
1440, 1800, 2160, 2880, 3024, 3600, 4320, 5040, 5400, 5760, 6048, 6480, 7056, 7200, 7560, 7920, 8064, 8640, 9000, 9072, 9360, 9504, 9720, 10080, 10584, 10800, 11088, 11520, 11880, 12096, 12240, 12600, 12960, 13680, 14040, 14112, 14400, 15120 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 1000 terms from Harry J. Smith)
PROG
(PARI) u(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d));
j=[]; for(n=1, 20000, if(sigma(n)-u(n)>2*n, j=concat(j, n))); j
(PARI) u(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d))
{ n=0; for (m=1, 10^9, if(sigma(m) - u(m) > 2*m, write("b063846.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 01 2009
CROSSREFS
Sequence in context: A081426 A101998 A174277 * A252186 A179691 A078095
KEYWORD
easy,nonn
AUTHOR
Jason Earls, Aug 25 2001
STATUS
approved

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Last modified June 15 18:41 EDT 2024. Contains 373410 sequences. (Running on oeis4.)