A218486 Positive numbers differing from next 2 greater squares by squares.

48, 96, 160, 240, 288, 336, 448, 480, 576, 720, 960, 1008, 1344, 1440, 1728, 2016, 2160, 2400, 2640, 2688, 3168, 3360, 3456, 3744, 4320, 4368, 4480, 5040, 5280, 5760, 6336, 6720, 7200, 7488, 8640, 8736, 8800, 9408, 10080, 10560, 10800, 11520, 12096, 12480

Offset: 1

Author

Michel Marcus, Oct 30 2012

Keywords

• nonn

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

Examples

			48 = 7^2 - 1^2 = 8^2 - 4^2.
		

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.

Crossrefs

Cf. A173121, A218485, A218487, A218488.

Programs

PARI

sq2(n) = {for (i=1, n, a = sqrtint(i) + 1; if (issquare(a^2-i) && issquare((a+1)^2-i), print1(i, ", ")););}