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A316908 a(n) is the smallest k with n prime factors such that 2^(k-1) == 1 (mod k) and p-1 does not divide k-1 for every prime p dividing k. 0
7957, 617093, 134564501, 384266404601, 8748670222601, 6105991025919737, 901196605940857381 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

Conjecture: a(n) > A006931(n) for every n > 2.

a(6)-a(8) derived from Feitsma's tables of pseudoprimes. a(9) > 2^64. - Giovanni Resta, Jul 19 2018

From Daniel Suteu, Jun 08 2020: (Start)

a(9)  <= 521957994426556057126261,

a(10) <= 1315856103949347820015303981,

a(11) <= 6357507186189933506573017225316941,

a(12) <= 77822245466150976053960303855104674781. (End)

LINKS

Table of n, a(n) for n=2..8.

Jan Feitsma and William Galway, Tables of pseudoprimes and related data

CROSSREFS

Cf. A001567, A121707, A316907.

Sequence in context: A316906 A316907 A293623 * A254138 A157660 A236786

Adjacent sequences:  A316905 A316906 A316907 * A316909 A316910 A316911

KEYWORD

nonn,more

AUTHOR

Thomas Ordowski, Jul 16 2018

EXTENSIONS

More terms from Michel Marcus, Jul 16 2018

a(6)-a(8) from Giovanni Resta, Jul 19 2018

STATUS

approved

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Last modified January 22 21:47 EST 2022. Contains 350504 sequences. (Running on oeis4.)