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A309806 Values of k in k-imperfect numbers. 2


%S 1,2,3,2,2,3,3,2,2,3,3,2,3,3,3,3,3,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,2,3,

%T 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3

%N Values of k in k-imperfect numbers.

%C The value of k in k-imperfect numbers, A127724. Except for the first term, all terms are > 1.

%C It appears that the first instance of a(n)=4 is for n=98 (993803899780063855042560), while no integer is currently known to be 5-imperfect. - _Michel Marcus_, Aug 20 2019

%H Michel Marcus, <a href="/A309806/a309806.gp.txt">PARI script</a>

%e The first 3 terms of A127724 are 1, 2, and 6, that are respectively 1-, 2-, and 3-imperfect. So the first 3 terms of this sequence are 1, 2 and 3.

%o (PARI) lista(lim) = {my(v = []); for (i=1, 4, my(vi = solveIMP(1, i, lim)); v = concat (v, vi);); apply(x->x/rhon(x), vecsort(v));} \\ uses the script in links section

%o lista(10^24) \\ to get 98 terms; _Michel Marcus_, Aug 20 2019

%Y Cf. A127724, A127725 (2-imperfect), A127726 (3-imperfect).

%K nonn,more

%O 1,2

%A _Jud McCranie_, Aug 17 2019

%E a(45)-a(50) from _Giovanni Resta_, Aug 19 2019

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Last modified December 13 01:23 EST 2019. Contains 329963 sequences. (Running on oeis4.)