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A175131 2^(n-1) mod semiprime(n). 2
1, 2, 4, 8, 2, 2, 1, 18, 6, 18, 1, 8, 1, 22, 4, 16, 23, 2, 14, 2, 52, 2, 49, 2, 10, 65, 64, 8, 44, 2, 64, 2, 42, 12, 62, 56, 31, 98, 81, 50, 74, 2, 1, 128, 96, 71, 60, 7, 81, 16, 94, 146, 1, 144, 108, 154, 133, 4, 46, 153, 67, 44, 88, 90, 198, 32, 14, 117 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

MATHEMATICA

Module[{nn=300, sems, len}, sems=Select[Range[nn], PrimeOmega[#]==2&]; len = Length[sems]; PowerMod[2, #[[1]]-1, #[[2]]]&/@Thread[{Range[len], sems}]] (* Harvey P. Dale, May 19 2018 *)

PROG

(PARI) lista(nn) = {semip = select(n->bigomega(n) == 2, vector(nn, i, i)); for (i=1, #semip, print1(2^(i-1) % semip[i], ", "); ); } \\ Michel Marcus, Sep 11 2013

CROSSREFS

Cf. A000079, A001358, A175036, A181615.

Sequence in context: A097892 A197282 A215452 * A033921 A167420 A195711

Adjacent sequences:  A175128 A175129 A175130 * A175132 A175133 A175134

KEYWORD

nonn,less

AUTHOR

Juri-Stepan Gerasimov, Dec 02 2010

EXTENSIONS

More terms from Michel Marcus, Sep 11 2013

STATUS

approved

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Last modified May 12 13:02 EDT 2021. Contains 343823 sequences. (Running on oeis4.)