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A000415 Numbers that are the sum of 2 but no fewer nonzero squares. +0
4
2, 5, 8, 10, 13, 17, 18, 20, 26, 29, 32, 34, 37, 40, 41, 45, 50, 52, 53, 58, 61, 65, 68, 72, 73, 74, 80, 82, 85, 89, 90, 97, 98, 101, 104, 106, 109, 113, 116, 117, 122, 125, 128, 130, 136, 137, 145, 146, 148, 149, 153, 157, 160, 162, 164, 170, 173, 178, 180, 181 (list; graph; listen)
OFFSET

1,1

COMMENT

Only these numbers can occur as discriminants of quintic polynomials with solvable Galois group F20. - Artur Jasinski (grafix(AT)csl.pl), Oct 25 2007

LINKS

T. D. Noe, Table of n, a(n) for n=1..10000

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Index entries for sequences related to sums of squares

FORMULA

Equals A000404 - A134422 - Artur Jasinski (grafix(AT)csl.pl), Oct 25 2007

MATHEMATICA

c = {}; Do[Do[k = a^2 + b^2; If[IntegerQ[Sqrt[k]], [null], AppendTo[c, k]], {a, 1, 100}], {b, 1, 100}]; Union[c] - Artur Jasinski (grafix(AT)csl.pl), Oct 25 2007

CROSSREFS

Cf. A000404, A000419, A001481, A002828.

Cf. A009003, A134422.

Sequence in context: A000404 A025284 A140328 this_sequence A096691 A070216 A100829

Adjacent sequences: A000412 A000413 A000414 this_sequence A000416 A000417 A000418

KEYWORD

nonn,nice

AUTHOR

njas and J. H. Conway (conway(AT)math.princeton.edu)

EXTENSIONS

More terms from Arlin Anderson (starship1(AT)gmail.com)

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Last modified December 4 21:35 EST 2008. Contains 151309 sequences.


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