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A072471 Squares such that the sum of two neighboring term is also a square. 0

%I #3 Dec 05 2013 19:55:20

%S 0,25,144,256,900,1600,1764,3136,8100,14400,15876,28224,50176,129600,

%T 142884,254016,302500,1742400,1920996,3415104,3956121,7033104,8767521,

%U 15586704,27709696,64834704,94303521,167650704,298045696,617621904

%N Squares such that the sum of two neighboring term is also a square.

%C The sequence is unbounded.

%e 144 is a term as 144 + 25 ( the previous term ) = 169 is a square and also 144 + 1225 ( the next term ) = 1369 = 37^2.

%t a[0] = 0; a[1] = 25; a[n_] := a[n] = (k = Sqrt[a[n - 1]] + 1; While[ !IntegerQ[ Sqrt[a[n - 1] + k^2]], k++ ]; k^2); Table[ a[n], {n, 0, 30}]

%Y Cf. A072470.

%K nonn

%O 0,2

%A _Amarnath Murthy_, Jun 20 2002

%E Edited by _Robert G. Wilson v_, Jun 21 2002

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Last modified April 24 03:08 EDT 2024. Contains 371918 sequences. (Running on oeis4.)