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 A175874 a(n) = least number such that sigma(a(n)+n)=n*sigma(a(n)). 2
 14, 118, 3, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(1)= A002961(1). a(2)= A175876(1), a(3)= A175875(1). - Zak Seidov, Jul 07 2013 Is n = 2 the only solution for sigma(n+4)=4*sigma(n)? - Zak Seidov, Jul 07 2013 A further solution to sigma(n+4)=4*sigma(n), and the terms a(5) and a(6), if they exist, they are all larger than 3*10^12. - Giovanni Resta, Jun 06 2016 LINKS EXAMPLE sigma(14+1)/sigma(14)=24/24=1, sigma(118+2)/sigma(118)=360/180=2, sigma(3+3)/sigma(3)=12/4=3, sigma(4+4)/sigma(2)=12/3=4. CROSSREFS Cf. A000203 sigma(n), A002961 sigma(n) = sigma(n+1). Cf. A175875, A175876. - Zak Seidov, Jul 07 2013 Sequence in context: A279855 A128569 A138431 * A006223 A091303 A241463 Adjacent sequences:  A175871 A175872 A175873 * A175875 A175876 A175877 KEYWORD more,nonn AUTHOR Zak Seidov, Oct 06 2010 STATUS approved

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Last modified December 1 13:40 EST 2020. Contains 338843 sequences. (Running on oeis4.)