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A208157 9-Knödel numbers. 7
21, 27, 45, 63, 99, 105, 117, 153, 171, 189, 207, 261, 273, 279, 333, 369, 387, 423, 429, 477, 513, 531, 549, 585, 603, 639, 657, 711, 747, 801, 873, 909, 927, 945, 963, 981, 1017, 1143, 1179, 1197, 1209, 1233, 1251, 1341, 1359, 1365, 1413, 1467, 1503, 1557 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Knödel Numbers

MAPLE

with(numtheory);

knodel:=proc(i, k)

local a, n, ok;

for n from k+1 to i do

ok:=1;

for a from 1 to n do

if gcd(a, n)=1 then if (a^(n-k) mod n)<>1 then ok:=0; break; fi; fi;

od;

if ok=1 then print(n); fi;

od;

end:

knodel(10000, 9)

MATHEMATICA

Select[Range[12, 1560, 3], Divisible[# - 9, CarmichaelLambda[#]]&] (* Jean-François Alcover, Mar 01 2018 *)

CROSSREFS

Cf. A002997, A050990, A033553, A050992, A050993, A208154-A208156, A208158.

Sequence in context: A144415 A098898 A098768 * A114168 A103083 A120735

Adjacent sequences: A208154 A208155 A208156 * A208158 A208159 A208160

KEYWORD

nonn

AUTHOR

Paolo P. Lava, Feb 24 2012

STATUS

approved

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Last modified November 29 08:47 EST 2022. Contains 358422 sequences. (Running on oeis4.)