OFFSET
1,2
COMMENTS
The smallest corresponding p are {3, 5, 2, 3, 5, 3, 7, 13, 2, 11, 13, 3, 19, 17, 3, 2, 23, 29, 31, 29, 7, 3, 37,...}
FORMULA
Complement of A187884.
EXAMPLE
21 is in the sequence because 21*3 + 1 = 8^2, with p = 3.
MAPLE
with(numtheory): for k from 1 to 120 do : q:=0:for p from 1 to 200 do : x:=sqrt(k*p+1)
: if x=trunc(x) and type(p, prime)=true and q=0 then q:=1: printf(`%d, `, k):else
fi:od:od:
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Mar 15 2011
STATUS
approved