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A340731 Numbers k such that A067439(k) is prime. 3
10, 15, 25, 27, 29, 31, 33, 36, 37, 44, 54, 64, 69, 78, 81, 82, 88, 102, 106, 110, 121, 142, 148, 177, 183, 192, 211, 212, 240, 270, 272, 274, 280, 314, 332, 337, 338, 344, 367, 381, 384, 404, 412, 421, 429, 434, 460, 463, 467, 490, 502, 511, 519, 523, 530, 551, 559, 584, 586, 588, 614, 624, 628 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

a(3) = 25 is a term because A067439(25) = 83 is prime.

MAPLE

filter:= proc(n) local t, k;

   isprime(add(`if`(igcd(n, k)=1, n mod k, 0), k=2..n-1))

end proc:

select(filter, [$1..1000]);

PROG

(PARI) isok(n) = isprime(sum(i=1, n-1, if(gcd(n, i)==1, n%i))); \\ Michel Marcus, Jan 18 2021

CROSSREFS

Cf. A067439, A340736.

Sequence in context: A272779 A173477 A091022 * A133372 A100916 A001750

Adjacent sequences:  A340728 A340729 A340730 * A340732 A340733 A340734

KEYWORD

nonn

AUTHOR

J. M. Bergot and Robert Israel, Jan 17 2021

STATUS

approved

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Last modified April 14 22:47 EDT 2021. Contains 342971 sequences. (Running on oeis4.)