A340731 Numbers k such that A067439(k) is prime.

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

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