A. GRYTCZUK

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135

X joined in G to an odd number of vertices in

or there exists

Y

Y joined in G to an odd number of

vertices in

.

Cremona-Odoni Theorem: [1] If n and

dD

d

,

is an odd graph then is negative Pellian.

d

Remark: If the Diophantine equation

has a solution in positive integers

22

xd=1y

y

then the number is called as negative Pellian.

d

From this Remark, Theorem 2 and The Cremona-

Odoni theorem it follows the following Corollary:

Corollary 2: If and ,

n

dDn2

d is an odd

graph, then

>1.hd

6. References

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14 ,

k

Qa

” Acta Mathematica Sinica,

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