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Numbers n such that n, n+1 and n+2 have the same number of anti-divisors.
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%I #9 Dec 15 2017 17:35:58

%S 19,74,90,102,148,187,204,212,213,231,232,233,328,329,351,457,469,519,

%T 546,547,555,573,756,859,868,869,870,879,980,981,991,1025,1080,1081,

%U 1096,1120,1121,1122,1132,1158,1211,1413,1420,1430,1431,1441,1467,1482

%N Numbers n such that n, n+1 and n+2 have the same number of anti-divisors.

%C See A066272 for definition of anti-divisor.

%t at[n_] := Count[Flatten[Quotient[#, Rest[Select[Divisors[#], OddQ]]] & /@ (2 n + Range[-1, 1])], Except[1]]; Select[Range[1485], at[#] == at[# + 1] == at[# + 2] &] (* _Jayanta Basu_, Jul 01 2013 *)

%Y Cf. A066272.

%K nonn

%O 1,1

%A _Jason Earls_, Aug 31 2002