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A352616 Numbers k such that A155085(k) is in A037074. 0
7, 17, 50, 71, 449, 851, 881, 1467, 2591, 5123, 9521, 18167, 29817, 34859, 38027, 39761, 52415, 84359, 90611, 92711, 106721, 147267, 179999, 204479, 206081, 342791, 388961, 596231, 606609, 847601, 922607, 1060307, 1256879, 1292831, 1389671, 1590983, 1976015, 2157227, 2169971, 2268449, 2571911 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Numbers k such that k + A000203(k) is the product of a twin prime pair.
LINKS
EXAMPLE
a(3) = 50 is a term because 50 + A000203(50) = 143 = 11*13 where (11,13) is a twin prime pair.
MAPLE
filter:= proc(n) local t, s; t:= n + numtheory:-sigma(n);
if t::even or not issqr(t+1) then return false fi;
s:= sqrt(t+1);
isprime(s+1) and isprime(s-1)
end proc:
select(filter, [$1..3000000]);
CROSSREFS
Sequence in context: A045821 A262754 A115914 * A094534 A262106 A371715
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Mar 23 2022
STATUS
approved

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Last modified May 27 21:52 EDT 2024. Contains 372882 sequences. (Running on oeis4.)