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Integers equal to the sum of divisors of their anti-divisors.
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%I #16 Aug 19 2024 11:38:21

%S 3,4,16,61,1861,4979,90191,58981439,10024953661

%N Integers equal to the sum of divisors of their anti-divisors.

%C Tested up tp 2*10^10. - _Giovanni Resta_, Aug 19 2024

%e Anti-divisors of 1861 are 2, 3, 17, 51, 61, 73, 219, 1241 and

%e sum of sigmas = 3 + 4 + 18 + 72 + 62 + 74 + 296 + 1332 = 1861.

%Y Cf. A000203, A066417, A178029.

%K nonn,hard,more

%O 1,1

%A _Paolo P. Lava_, Aug 17 2024

%E a(8)-a(9) from _Giovanni Resta_, Aug 19 2024