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%I #18 Sep 08 2022 08:46:09
%S 15456,16920,48576,59520,107160,153360,232596,281916,306720,332280,
%T 332640,358560,360360,373104,383400,514080,548772,556920,788256,
%U 876960,884520,930384,943344,950040,955296,1234464,1357020,1396440,1421280,1534080,1539720,1582866
%N Numbers n such that sigma(n+sigma(n)) = 5*sigma(n).
%e Number 15456 (with sigma(15456) = 48384) is in sequence because sigma(15456+sigma(15456)) = sigma(63840) = 241920 = 5*48384.
%p with(numtheory): A246912:=n->`if`(sigma(n+sigma(n)) = 5*sigma(n),n,NULL): seq(A246912(n), n=1..10^6); # _Wesley Ivan Hurt_, Sep 07 2014
%t Select[Range[16*10^5],DivisorSigma[1,#+DivisorSigma[1,#]] == 5*DivisorSigma[ 1,#]&] (* _Harvey P. Dale_, Mar 13 2016 *)
%o (Magma) [n:n in[1..10^7] | SumOfDivisors(n+SumOfDivisors(n))eq 5*SumOfDivisors(n)]
%o (PARI)
%o for(n=1,10^7,if(sigma(n+sigma(n))==5*sigma(n),print1(n,", "))) \\ _Derek Orr_, Sep 07 2014
%Y Cf. A000203, A246456, A246909, A246910, A246911, A246913, A246914, A274535 (5*sigma(n)).
%K nonn
%O 1,1
%A _Jaroslav Krizek_, Sep 07 2014