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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 (list; table; graph; refs; listen; history; text; internal format)
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 - (k-n 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

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Last modified September 22 14:20 EDT 2020. Contains 337291 sequences. (Running on oeis4.)