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A328418 Records in A328412. 2
2, 4, 7, 11, 12, 13, 15, 16, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Companion sequence of A328417.

Conjecture: this sequence is infinite. That is to say, A328412 is unbounded.

LINKS

Table of n, a(n) for n=1..9.

Wikipedia, Multiplicative group of integers modulo n

EXAMPLE

Let (Z/mZ)* be the multiplicative group of integers modulo m. We have (Z/mZ)* = C_2 X C_60 has 11 solutions, namely m = 143, 155, 175, 183, 225, 244, 286, 310, 350, 366, 450; for all k' < 30, (Z/mZ)* = C_2 X C_(2k') has fewer than 11 solutions. So A328412(30) = 11 is a term.

PROG

(PARI) my(t=0); for(k=1, 5000, if(A328412(k)>t, print1(a(k), ", "); t=A328412(k)))

CROSSREFS

Cf. A328412, A328417.

Sequence in context: A333716 A091263 A101430 * A249594 A127575 A240106

Adjacent sequences:  A328415 A328416 A328417 * A328419 A328420 A328421

KEYWORD

nonn,hard,more

AUTHOR

Jianing Song, Oct 14 2019

STATUS

approved

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Last modified June 15 12:29 EDT 2021. Contains 345048 sequences. (Running on oeis4.)