

A198787


Triangle of edge counts for the (n,k)Turán graphs.


1



0, 0, 1, 0, 2, 3, 0, 4, 5, 6, 0, 6, 8, 9, 10, 0, 9, 12, 13, 14, 15, 0, 12, 16, 18, 19, 20, 21, 0, 16, 21, 24, 25, 26, 27, 28, 0, 20, 27, 30, 32, 33, 34, 35, 36, 0, 25, 33, 37, 40, 41, 42, 43, 44, 45, 0, 30, 40, 45, 48, 50, 51, 52, 53, 54, 55, 0, 36, 48, 54, 57, 60, 61, 62, 63, 64, 65, 66, 0, 42
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OFFSET

1,5


LINKS

Table of n, a(n) for n=1..80.
Wikipedia, Turán graph


FORMULA

t(n,k) = (n^2  (n mod k) ceiling(n/k)^2  (kn mod k) floor(n/k)^2)/2


MATHEMATICA

Flatten[Table[(n^2  Mod[n, k] Ceiling[n/k]^2  (k  Mod[n, k]) Floor[n/k]^2)/2, {n, 20}, {k, n}]]


CROSSREFS

Cf. A193331 (upper bound of this sequence).
Sequence in context: A007945 A011150 A100112 * A193331 A091246 A271439
Adjacent sequences: A198784 A198785 A198786 * A198788 A198789 A198790


KEYWORD

tabl,easy,nonn


AUTHOR

Chao Xu, Oct 29 2011


STATUS

approved



