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A009003 Hypotenuse numbers (squares are sums of 2 distinct nonzero squares). +0
17
5, 10, 13, 15, 17, 20, 25, 26, 29, 30, 34, 35, 37, 39, 40, 41, 45, 50, 51, 52, 53, 55, 58, 60, 61, 65, 68, 70, 73, 74, 75, 78, 80, 82, 85, 87, 89, 90, 91, 95, 97, 100, 101, 102, 104, 105, 106, 109, 110, 111, 113, 115, 116, 117, 119, 120, 122, 123, 125, 130, 135, 136, 137, 140 (list; graph; listen)
OFFSET

1,1

COMMENT

Multiples of Pythagorean primes A002144 or of primitive Pythagorean triangles' hypotenuses A008846. - Lekraj Beedassy (blekraj(AT)yahoo.com), Nov 12 2003

It appears that this is exactly the sequence of positive integers with at least one prime divisor of the form 4k+1. (This has been verified for all terms<=500.) Compare A072592. - John W. Layman (layman(AT)math.vt.edu), Mar 12 2008

REFERENCES

S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 98-104.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

S. R. Finch, Landau-Ramanujan Constant

Ron Knott, Pythagorean Triples and Online Calculators

Index entries for sequences related to sums of squares

R. Chapman, Pythagorean triples and sums of squares

CROSSREFS

Cf. A009000, A009003, A024507, A004431. Complement of A004144.

Primitive elements give A002144.

Cf. A072592.

Sequence in context: A049197 A009000 A057100 this_sequence A071821 A084645 A092604

Adjacent sequences: A009000 A009001 A009002 this_sequence A009004 A009005 A009006

KEYWORD

nonn

AUTHOR

David W. Wilson (davidwwilson(AT)comcast.net)

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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