OFFSET
1,2
EXAMPLE
38 is in the sequence because L(38/83) = L(83/38) = 1, where L(a/b) is the Legendre symbol of a and b, which is defined to be 1 if a is a quadratic residue (mod b) and -1 if a is a quadratic non-residue (mod b).
MAPLE
with(numtheory): for n from 1 to 300 do: s:=0:l:=length(n):for q from 0 to
l-1 do:x:=iquo(n, 10^q):y:=irem(x, 10):s:=s+y*10^(l-1-q): od: if quadres(n, s)=1
and quadres(s, n)=1 then printf(`%d, `, n):else fi:od:
CROSSREFS
KEYWORD
nonn,base,changed
AUTHOR
Michel Lagneau, Dec 13 2010
STATUS
approved