cp's OEIS Frontend

A137532 a(n) is the smallest positive integer k such that d(k) = d(k+n) = 2*n, where d(m) (A000005) is the number of positive divisors of m, or 0 if no such k exists.

%I A137532 #16 May 09 2021 04:53:37
%S A137532 2,6,172,66,15952,84,22592,888,2196,3750,459932661,660,86817796083,
%T A137532 185152,143366096,5304,17685013528576,3150,1786574475624429,1272510,
%U A137532 29059703104,12872682,4817557477673402368,9576,85608255863,15744471040,1179648,124718750,1765038427619364800823267
%N A137532 a(n) is the smallest positive integer k such that d(k) = d(k+n) = 2*n, where d(m) (A000005) is the number of positive divisors of m, or 0 if no such k exists.
%o A137532 (PARI) lq080419b(n,a)=n*=2; until(0,numdiv(a++)==n || next; numdiv(a+n\2)==n && break); a
%o A137532 for(i=1,99,print1(lq080419b(i)", "))
%Y A137532 Cf. A000005, A139416.
%K A137532 nonn
%O A137532 1,1
%A A137532 _M. F. Hasler_, Apr 19 2008
%E A137532 a(11) from _Jacques Tramu_, Apr 20 2008
%E A137532 More terms from _Jinyuan Wang_, May 08 2021