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A180061 Numbers n such that (2^(2^n mod n) mod n)=4. 1
5, 6, 7, 9, 11, 12, 13, 17, 19, 21, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 63, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 133, 137, 139, 149, 151, 157, 163, 167, 172, 173, 179, 181, 190, 191, 193, 196, 197, 199, 211 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The composite terms in this sequence start 6, 9, 12, 21, 63, 121, 133, 172, 190, 196,.. - R. J. Mathar, Jan 14 2011

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

A180060(a(n))=4.

MATHEMATICA

Select[Range[300], PowerMod[2, PowerMod[2, #, #], #]==4&] (* Harvey P. Dale, Sep 08 2016 *)

PROG

(PARI) s=[]; for(n=1, 1000, if((2^(2^n%n)%n)==4, s=concat(s, n))); s \\ Colin Barker, Jun 27 2014

CROSSREFS

Cf. A000040, A000079, A179976, A180060.

Sequence in context: A279195 A232710 A132829 * A196029 A096820 A175154

Adjacent sequences:  A180058 A180059 A180060 * A180062 A180063 A180064

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jan 14 2011

EXTENSIONS

Terms corrected by R. J. Mathar, Jan 14 2011

STATUS

approved

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Last modified October 17 18:58 EDT 2019. Contains 328127 sequences. (Running on oeis4.)