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 A342630 Numbers k such that A340180(k) is prime. 2
 5, 6, 7, 14, 18, 24, 29, 34, 39, 41, 47, 53, 77, 114, 119, 148, 150, 159, 176, 188, 189, 190, 191, 205, 215, 217, 218, 241, 268, 288, 312, 314, 331, 334, 339, 342, 346, 352, 364, 367, 387, 390, 402, 418, 429, 438, 439, 440, 446, 449, 480, 493, 494, 500, 504, 510, 521, 523, 546, 549, 553, 561, 580 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..5000 EXAMPLE a(4) = 14 is a term because A340180(14) = 23 is prime. MAPLE f:= proc(n) local s, k; s:= numtheory:-sigma(n); add(`if`(igcd(n, k)=1, s mod k, 0), k=1..n-1); end proc: select(t -> isprime(f(t)), [\$1..1000]); CROSSREFS Cf. A340180. Sequence in context: A371029 A111018 A326132 * A347807 A161925 A078694 Adjacent sequences: A342627 A342628 A342629 * A342631 A342632 A342633 KEYWORD nonn AUTHOR J. M. Bergot and Robert Israel, Mar 17 2021 STATUS approved

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Last modified September 16 02:10 EDT 2024. Contains 375959 sequences. (Running on oeis4.)