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A346991 Numbers occurring as divisors of 2^k + 5^k, k > 0. 1
1, 7, 11, 17, 19, 23, 29, 37, 41, 47, 49, 53, 59, 61, 73, 77, 89, 97, 101, 103, 109, 113, 121, 127, 131, 133, 137, 139, 149, 161, 167, 173, 179, 181, 193, 209, 211, 223, 229, 233, 241, 251, 253, 257, 259, 263, 269, 277, 281, 287, 289, 313, 317, 329, 331, 337, 343 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
If k is a term, then so are all divisors of k. - Robert Israel, Dec 08 2022
LINKS
MAPLE
filter:= proc(n) local q, v;
if igcd(n, 10) <> 1 then return false fi;
q:= 5/2 mod n;
traperror(NumberTheory:-ModularLog(-1, q, n)) <> lasterror
end proc:
filter(1):= true:
select(filter, [$1..400]); # Robert Israel, Dec 08 2022
CROSSREFS
Sequence in context: A034849 A269256 A106070 * A038880 A019365 A191055
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Aug 11 2021
STATUS
approved

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Last modified April 12 20:38 EDT 2024. Contains 371639 sequences. (Running on oeis4.)