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%I #19 Sep 23 2013 06:08:50
%S 21098,134930,343027,361730,387127,751394,793595,1344517,1430449,
%T 1579394,1794854,3542797,5022254,7930117,9241627,12122947,21089129,
%U 21928717,49825117,70233329,78795074,90079589,95208734,110995807,124648303,124964219,144871634
%N Composite squarefree numbers n such that p+d(n) divides n+d(n), where p are the prime factors of n and d(n) the number of divisors of n.
%C Subsequence of A120944.
%H Donovan Johnson, <a href="/A228299/b228299.txt">Table of n, a(n) for n = 1..100</a>
%e Prime factors of 21098 are 2, 7, 11 and 137 while d(21098) = 16. We have that 21098 + 16 = 21114 and 21114 / (2 + 16) = 1173, 21114 / (7 + 16) = 918, 21114 / (11 + 16) = 782 and 21114 / (137 + 16) = 138.
%p with (numtheory); P:=proc(q) local a,i,ok,n;
%p for n from 1 to q do if not isprime(n) then a:=ifactors(n)[2]; ok:=1;
%p for i from 1 to nops(a) do if a[i][2]>1 then ok:=0; break;
%p else if not type((n+tau(n))/(a[i][1]+tau(n)),integer) then ok:=0; break; fi; fi; od; if ok=1 then print(n); fi; fi; od; end: P(10^6);
%Y Cf. A000005, A228300-A228302.
%K nonn
%O 1,1
%A _Paolo P. Lava_, Aug 20 2013
%E More terms from _Michel Marcus_, Sep 21 2013
%E Deleted first term from _Paolo P. Lava_, Sep 23 2013
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