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A309806 Values of k in k-imperfect numbers. 2
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, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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

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

LINKS

Table of n, a(n) for n=1..50.

Michel Marcus, PARI script

EXAMPLE

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.

PROG

(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

lista(10^24) \\ to get 98 terms; Michel Marcus, Aug 20 2019

CROSSREFS

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

Sequence in context: A281976 A300708 A240755 * A256170 A051686 A079294

Adjacent sequences:  A309803 A309804 A309805 * A309808 A309809 A309810

KEYWORD

nonn,more

AUTHOR

Jud McCranie, Aug 17 2019

EXTENSIONS

a(45)-a(50) from Giovanni Resta, Aug 19 2019

STATUS

approved

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Last modified November 16 17:04 EST 2019. Contains 329201 sequences. (Running on oeis4.)