A004305 Simple triangulations of a disk: column 4 of square array in A210664. (Formerly M3091)

3, 22, 85, 254, 644, 1448, 2967, 5645, 10109, 17214, 28093, 44212, 67430, 100064, 144959, 205563, 286007, 391190, 526869, 699754, 917608, 1189352, 1525175, 1936649, 2436849, 3040478, 3763997, 4625760, 5646154, 6847744, 8255423, 9896567, 11801195, 14002134, 16535189, 19439318, 22756812, 26533480, 30818839

Offset

0,1

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Andrew Howroyd, Table of n, a(n) for n = 0..1000

P. N. Rathie, A census of simple planar triangulations, J. Combin. Theory, B 16 (1974), 134-138.

Formula

a(n) = (n^6 + 15*n^5 + 103*n^4 + 405*n^3 + 976*n^2 + 1236*n + 432)/144.

Crossrefs

Cf. A210664.

Sequence in context: A075204 A106150 A135836 * A275290 A368478 A277228

Adjacent sequences: A004302 A004303 A004304 * A004306 A004307 A004308

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Entry revised by N. J. A. Sloane, Mar 27 2012

Status

approved