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A262104 Pseudoprimes to base 7, written in base 7. 7
6, 34, 643, 1431, 2023, 2245, 3136, 5215, 6061, 6601, 10121, 12361, 16123, 20032, 25345, 33155, 41545, 42601, 42652, 44122, 45406, 50026, 54561, 56035, 66522, 66666, 105403, 110254, 112612, 113345, 113356, 123616, 135206, 140011, 151142, 151354, 153022, 153101, 153352, 155554 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

a(n) = A007093(A005938(n)).

MATHEMATICA

base = 7; t = {}; n = 1;

While[Length[t] < 40, n++;

If[! PrimeQ[n] && PowerMod[base, n - 1, n] == 1,

  AppendTo[t, FromDigits@IntegerDigits[n, 7]]]]; t

FromDigits[IntegerDigits[#, 7]]&/@Select[Range[40000], CompositeQ[#] && PowerMod[ 7, #-1, #]==1&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Feb 24 2018 *)

PROG

(PARI) lista(nn, b=7) = {for (n=1, nn, if (Mod(b, n)^(n-1)==1 && !ispseudoprime(n) && n>1, print1(subst(Pol(digits(n, b), x), x, 10), ", "); ); ); } \\ Michel Marcus, Sep 30 2015

CROSSREFS

Cf. A005938 (pseudoprimes to base 7), A007093 (numbers in base 7).

Cf. A258189, A262101, A262102, A262103, A262105, A262154.

Sequence in context: A062819 A230246 A092336 * A161323 A003423 A230936

Adjacent sequences:  A262101 A262102 A262103 * A262105 A262106 A262107

KEYWORD

nonn,base

AUTHOR

Abdul Gaffar Khan, Sep 11 2015

STATUS

approved

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Last modified August 8 08:29 EDT 2022. Contains 356003 sequences. (Running on oeis4.)