OFFSET
2,1
COMMENTS
For each n >= 3, a(n) is divisible by n.
LINKS
Robert Israel, Table of n, a(n) for n = 2..3000
EXAMPLE
For n=6 the primes are 7 == 1 (mod 6) and 11 == 5 (mod 6), so a(6) = 7+11=18.
MAPLE
f:= proc(n) local t, k, p;
t:= 0:
for k from 1 to n-1 do
if igcd(k, n) = 1 then
for p from n+k by n do
if isprime(p) then
t:= t+p;
break
fi
od
fi
od;
t
end proc:
map(f, [$2..100]);
CROSSREFS
KEYWORD
nonn,look
AUTHOR
J. M. Bergot and Robert Israel, Jan 05 2021
STATUS
approved