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A339307
Numbers k such that A228553(k) is prime.
2
11, 20, 24, 27, 32, 35, 37, 38, 68, 74, 78, 79, 82, 96, 98, 101, 103, 122, 137, 149, 161, 188, 209, 218, 239, 249, 258, 276, 293, 321, 325, 333, 363, 365, 372, 433, 445, 449, 499, 535, 567, 568, 580, 588, 594, 595, 622, 644, 656, 663, 666, 682, 688, 693, 721, 742, 754, 756, 760, 796, 814, 845
OFFSET
1,1
LINKS
EXAMPLE
a(3) = 24 is in the sequence because A228553(24) = 1987 is prime.
MAPLE
f:= proc(n)
local S;
S:= select(t -> isprime(t) and isprime(2*n-t), [seq(i, i=3..n, 2)]);
add(t*(2*n-t), t=S)
end proc:
f(2):= 4:
select(isprime@f, [$1..1000]);
CROSSREFS
Sequence in context: A053715 A343770 A250203 * A038581 A044054 A044435
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Nov 29 2020
STATUS
approved