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A218487 Positive numbers differing from next 3 greater squares by squares. 3
720, 5040, 5760, 10080, 20160, 22176, 28800, 56160, 60480, 100800, 126720, 134640, 151200, 187200, 248976, 262080, 282240, 332640, 428400, 443520, 463680, 665280, 677376, 734400, 763776, 887040, 1108800, 1149120, 1190160, 1235520, 1497600, 1685376, 1718640 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are multiples of 144. - Zak Seidov, Nov 27 2013

LINKS

Donovan Johnson, 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

720 = 27^2 - 3^2 = 28^2 - 8^2 = 29^2 - 11^2.

MATHEMATICA

Select[Range[172*10^4], AllTrue[Sqrt[(Floor[Sqrt[#]]+{1, 2, 3})^2-#], IntegerQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 18 2021 *)

PROG

(PARI) sq3(n) = {for (i=1, n, a = sqrtint(i) + 1; if (issquare(a^2-i) && issquare((a+1)^2-i) && issquare((a+2)^2-i), print1(i, ", ")); ); }

CROSSREFS

Cf. A218485, A218486, A218488.

Sequence in context: A233787 A280920 A187290 * A053625 A052793 A179728

Adjacent sequences:  A218484 A218485 A218486 * A218488 A218489 A218490

KEYWORD

nonn

AUTHOR

Michel Marcus, Oct 30 2012

STATUS

approved

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Last modified October 18 08:19 EDT 2021. Contains 348066 sequences. (Running on oeis4.)