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A134422 Square numbers which are sums of 2 distinct nonzero squares. 5
25, 100, 169, 225, 289, 400, 625, 676, 841, 900, 1156, 1225, 1369, 1521, 1600, 1681, 2025, 2500, 2601, 2704, 2809, 3025, 3364, 3600, 3721, 4225, 4624, 4900, 5329, 5476, 5625, 6084, 6400, 6724, 7225, 7569, 7921, 8100, 8281, 9025, 9409, 10000, 10201 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..43.

Index entries for sequences related to sums of squares

FORMULA

a(n) = A009003(n)^2.

EXAMPLE

25 = 5^2 = 4^2 + 3^2, and so 25 is in the sequence.

100 = 10^2 = 8^2 + 6^2, and so 100 is in the sequence.

169 = 13^2 = 12^2 + 5^2, and so 169 is in the sequence.

MATHEMATICA

c = {}; Do[Do[k = a^2 + b^2; If[IntegerQ[Sqrt[k]], AppendTo[c, k]], {a, 1, b - 1}], {b, 200}]; Union[c] (* Artur Jasinski *)

Select[Range[100]^2, Length[PowersRepresentations[#, 2, 2]] > 1 &] (* Alonso del Arte, Feb 11 2014 *)

PROG

(PARI) select(n->for(k=1, sqrtint(n\2), if(issquare(n-k^2), return(n>k^2))); 0, vector(100, i, i^2)) \\ Charles R Greathouse IV, Jul 02 2013

CROSSREFS

Cf. A000404, A000415, A009003.

Sequence in context: A144854 A237202 A198385 * A016850 A221274 A042220

Adjacent sequences:  A134419 A134420 A134421 * A134423 A134424 A134425

KEYWORD

nonn

AUTHOR

Artur Jasinski, Oct 25 2007

STATUS

approved

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Last modified July 16 23:49 EDT 2019. Contains 325092 sequences. (Running on oeis4.)