OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..5000
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
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Nov 29 2020
STATUS
approved