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A057057 Let R(i,j) be the rectangle with antidiagonals 1; 2,3; 4,5,6; ...; C(n,3) is in antidiagonal a(n). 3
1, 3, 4, 6, 8, 11, 13, 15, 18, 21, 24, 27, 30, 33, 37, 40, 44, 48, 52, 55, 60, 64, 68, 72, 76, 81, 85, 90, 95, 100, 104, 109, 114, 119, 125, 130, 135, 141, 146, 152, 157, 163, 168, 174, 180, 186, 192, 198, 204, 210, 216, 223, 229 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

Table of n, a(n) for n=3..55.

FORMULA

Round(sqrt(2*binomial(n, 3))). - Vladeta Jovovic, Jun 14 2003

CROSSREFS

Cf. A057045, A057062, A057048, A022846, A057054.

Sequence in context: A109402 A020901 A181714 * A186154 A030761 A030711

Adjacent sequences:  A057054 A057055 A057056 * A057058 A057059 A057060

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jul 30 2000.

STATUS

approved

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Last modified April 7 19:49 EDT 2020. Contains 333306 sequences. (Running on oeis4.)