OFFSET
1,1
COMMENTS
All terms are even. The sequence is infinite. E.g., positive terms of A173121 {48, 288, 960, 2400, 5040, 9408, 16128, 25920, 39600,...} is infinite subsequence of A218486. - Zak Seidov, Nov 26 2013
Another infinite subsequence is {96, 480, 1440, 3360, 6720, 12096, 20160, ...} = 96 *binomial(m,4) = 96*(positive terms in A000332). - Zak Seidov, Nov 26 2013
LINKS
Zak Seidov, Table of n, a(n) for n = 1..1000
E. J. Barbeau, Numbers differing from consecutive squares by squares, Canad. Math. Bull. 28(1985), pp. 337-342.
EXAMPLE
48 = 7^2 - 1^2 = 8^2 - 4^2.
PROG
(PARI) sq2(n) = {for (i=1, n, a = sqrtint(i) + 1; if (issquare(a^2-i) && issquare((a+1)^2-i), print1(i, ", ")); ); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Oct 30 2012
STATUS
approved