OFFSET
1,2
COMMENTS
The terms a(1)=1 and a(3)=4 are the only squares in this sequence. - M. F. Hasler, Apr 22 2015
LINKS
Colin Barker, Table of n, a(n) for n = 1..1500
EXAMPLE
13 is in the sequence because there is only 1 solution to x^2 - y^2 = 13, namely (x,y) = (7,6).
MATHEMATICA
r[n_] := Reduce[x^2 - y^2 == n && x > y >= 0, {x, y}, Integers]; Reap[For[n = 1, n < 200, n++, If[r[n][[0]] === And, Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, Apr 22 2015 *)
PROG
(PARI) is(n)=A034178(n)==1 \\ M. F. Hasler, Apr 22 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Barker, Apr 22 2015
STATUS
approved