A246323 - OEIS

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A246323

Triangle read by rows: T(n,k) = number of normal planar lambda terms of size n with k free variables (n >= 1, 1 <= k <= n).

1, 2, 1, 9, 6, 2, 54, 40, 20, 5, 378, 295, 175, 70, 14, 2916, 2346, 1526, 756, 252, 42, 24057, 19739, 13587, 7602, 3234, 924, 132, 208494, 173426, 123978, 74964, 36828, 13728, 3432, 429

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

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..36.

Noam Zeilberger, Alain Giorgetti, A correspondence between rooted planar maps and normal planar lambda terms, arXiv:1408.5028 [cs.LO], 2014.

EXAMPLE

Triangle begins:

2,1

9,6,2

54,40,20,5

378,295,175,70,14

2916,2346,1526,756,252,42

24057,19739,13587,7602,3234,924,132,

208494,173426,123978,74964,36828,13728,3432,429

...

CROSSREFS

Cf. A000108, A000984, A000168, A246322.

Sequence in context: A235595 A061356 A141028 * A201685 A120671 A245461

Adjacent sequences: A246320 A246321 A246322 * A246324 A246325 A246326

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Aug 28 2014

STATUS

approved