cp's OEIS Frontend

A192285 Primitive pseudo anti-perfect numbers.

%I A192285 #7 Jul 22 2025 12:12:01
%S A192285 5,7,8,17,22,23,31,33,38,39,41,52,53,59,67,71,73,74,81,83,94,101,103,
%T A192285 108,109,116,122,127,129,137,143,149,151,157,158,167,171,172,178,179,
%U A192285 193,199,214,237,241,247,257,262,263,269,283,293,311,313,319,331,333
%N A192285 Primitive pseudo anti-perfect numbers.
%C A192285 A primitive pseudo anti-perfect number is a pseudo anti-perfect number that is not a multiple of any other pseudo anti-perfect number.
%C A192285 Like A006036 but using anti-divisors.
%C A192285 Subset of A192270.
%p A192285 with(combinat);
%p A192285 P:=proc(i)
%p A192285 local a,j,k,n,ok,S,v;
%p A192285 v:=array(1..10000); j:=0;
%p A192285 for n from 1 to i do
%p A192285   a:={};
%p A192285   for k from 2 to n-1 do
%p A192285     if abs((n mod k)- k/2) < 1 then a:=a union {k}; fi;
%p A192285   od;
%p A192285   S:=subsets(a);
%p A192285   while not S[finished] do
%p A192285     if convert(S[nextvalue](), `+`)=n then
%p A192285        if j=0 then j:=1; v[1]:=n; print(n); break;
%p A192285        else
%p A192285           ok:=1;
%p A192285           for k from 1 to j do
%p A192285               if trunc(n/v[k])=n/v[k] then ok:=0; break; fi;
%p A192285           od;
%p A192285           j:=j+1; v[j]:=n; if ok=1 then print(n); fi;
%p A192285        fi;
%p A192285     fi;
%p A192285   od;
%p A192285 od;
%p A192285 end:
%Y A192285 Cf. A006036, A066272, A192270
%K A192285 nonn
%O A192285 1,1
%A A192285 _Paolo P. Lava_, Jul 20 2011