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%I #8 Sep 08 2022 08:46:08
%S 1,2,15,20,104,207,464,650,1023,1952,2975,19359,130304,147455,522752,
%T 1207359,5017599,8382464
%N Numbers n such that floor(antisigma(n) / n) = antisigma(n) mod n.
%C Antisigma(n) = A024816(n) = sum of numbers less than n which do not divide n.
%C Also numbers n such that there is some number k > 0 with property: antisigma(n) = k*(n+1). Corresponding values of numbers k: 0, 0, 6, 8, 50, 102, 230, 323, 510, 974, 1486, 9678, …
%C Numbers n such that A244325(n) = A229110(n).
%e Antisigma(19359) = 187366080 = 9678*19359 + 9678.
%o (Magma) [n: n in [1..1000000] | u eq 0 where u is (Floor((((n*(n+1)) div 2 - SumOfDivisors(n)) div n))) - (((((n*(n+1)) div 2)-SumOfDivisors(n)) mod (n)))]
%o (PARI) isok(n) = my(as = n*(n+1)/2 - sigma(n)); (as\n == as % n); \\ _Michel Marcus_, Jun 26 2014
%Y Cf. A024816, A244325, A229110.
%K nonn
%O 1,2
%A _Jaroslav Krizek_, Jun 25 2014
%E a(16)-a(18) from _Michel Marcus_, Jun 26 2014