cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A244324 Numbers n such that floor(antisigma(n) / n) = antisigma(n) mod n.

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%I A244324 #8 Sep 08 2022 08:46:08
%S A244324 1,2,15,20,104,207,464,650,1023,1952,2975,19359,130304,147455,522752,
%T A244324 1207359,5017599,8382464
%N A244324 Numbers n such that floor(antisigma(n) / n) = antisigma(n) mod n.
%C A244324 Antisigma(n) = A024816(n) = sum of numbers less than n which do not divide n.
%C A244324 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 A244324 Numbers n such that A244325(n) = A229110(n).
%e A244324 Antisigma(19359) = 187366080 = 9678*19359 + 9678.
%o A244324 (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 A244324 (PARI) isok(n) = my(as = n*(n+1)/2 - sigma(n)); (as\n == as % n); \\ _Michel Marcus_, Jun 26 2014
%Y A244324 Cf. A024816, A244325, A229110.
%K A244324 nonn
%O A244324 1,2
%A A244324 _Jaroslav Krizek_, Jun 25 2014
%E A244324 a(16)-a(18) from _Michel Marcus_, Jun 26 2014