A217004 - OEIS

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A217004

Numbers arising in computing the Turan function of cycles of length 4.

273, 307, 381, 553, 651, 757, 871, 993, 1057, 1407, 1723, 1893, 2257, 2451, 2863, 3541, 3783, 4161, 4557, 5113, 5403, 6321, 6643, 6973, 8011, 9507, 10303, 10713, 11557, 11991, 12883, 14763, 15751, 16257, 16513, 17293, 18907, 19461, 22351, 22953, 24807, 26733, 28057, 28731, 30103

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..45.

Z. Füredi, Graphs without quadrilaterals, J. Combin. Theory (A) 34 (1983), 187-190.

Z. Füredi, On the number of edges of quadrilateral-free graphs, J. Combin. Theory (B) 68 (1996), 1-6.

Oleg Pikhurko, A Note on the Turan Function of Even Cycles, Proc Amer Math Soc, 140 (2012) 3687-3992.

FORMULA

a(n) = q^2+q+1 where q=A000961(n+10). - R. J. Mathar, Jul 12 2013

CROSSREFS

Cf. A000961, A002061.