OFFSET
1,3
COMMENTS
a(n) = 0 for n = 1, 7, 100. Are there any other values?
No other zero up to n=200000. - Michel Marcus, Jan 31 2019
LINKS
Michel Marcus, Table of n, a(n) for n = 1..10000
EXAMPLE
a(2) = 1 because (2 + 3 + 5) mod 3 = 1.
a(7) = 0 because (2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41) mod 17 = 238 mod 17 = 0.
MATHEMATICA
Table[Mod[Sum[Prime@ k, {k, 2 n - 1}], Prime@ n], {n, 70}] (* Michael De Vlieger, Mar 24 2016 *)
PROG
(PARI) for(n=1, 1e2, print1(sum(k=1, 2*n-1, prime(k)) % prime(n), ", "));
(PARI) lista(nn) = {my(s=0, p=1); for (n=1, nn, p = nextprime(p+1); s += p; print1(s % prime(n), ", "); p = nextprime(p+1); s += p; ); } \\ Michel Marcus, Jan 31 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Altug Alkan, Mar 23 2016
STATUS
approved