OFFSET
0,2
COMMENTS
a(n) is the least k such that there are exactly n distinct primes of the form A007504(k) mod p for the first k primes p.
LINKS
Robert Israel, Table of n, a(n) for n = 0..1000
EXAMPLE
a(4) = 25 because A007504(25) = 1060 and there are 4 primes of the form 1060 mod p for the first 25 primes p: 2 = 1060 mod 23, 3 = 1060 mod 7, 7 = 1060 mod 13 and 23 = 1060 mod 61, and 25 is the first k that produces exactly 4 primes in this way.
MAPLE
N:= 100: # for a(0)..a(N)
V:= Array(0..N): count:= 0:
P:= {}: p:= 1: t:= 0:
for n from 1 while count < 100 do
p:= nextprime(p); P:= P union {p}; t:= t+p;
v:= nops(select(isprime, map(s -> t mod s, P)));
if v <= N and V[v] = 0 then
V[v]:= n; count:= count+1;
fi
od:
convert(V, list);
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Apr 29 2021
STATUS
approved