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A211312 Square array of Delannoy numbers D(i,j) mod 3 (i >= 0, j >= 0) read by antidiagonals. 5
1, 1, 1, 1, 0, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 2, 2, 0, 2, 2, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 2, 2, 2, 0, 0, 2, 2, 2, 1, 1, 1, 1, 2, 2, 0, 2, 2, 1, 1, 1, 1, 0, 1, 2, 0, 2, 2, 0, 2, 1, 0, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,8

LINKS

Table of n, a(n) for n=0..90.

Marko Razpet, A self-similarity structure generated by king's walk, Algebraic and topological methods in graph theory (Lake Bled, 1999). Discrete Math. 244 (2002), no. 1-3, 423--433. MR1844050 (2002k:05022)

FORMULA

a(n) = sum(binomial(k, j) * binomial(n-j, k), j=0..n-k) mod 3. - Johannes W. Meijer, Jul 19 2013

EXAMPLE

Written as a triangle:

1,

1, 1,

1, 0, 1,

1, 2, 2, 1,

1, 1, 1, 1, 1,

1, 0, 1, 1, 0, 1,

1, 2, 2, 0, 2, 2, 1,

1, 1, 1, 0, 0, 1, 1, 1,

1, 0, 1, 0, 0, 0, 1, 0, 1,

...

MAPLE

A211312 := proc(n, k): add(binomial(k, j) * binomial(n-j, k), j=0..n-k) mod 3 end: seq(seq(A211312(n, k), k=0..n), n=0..12); # Johannes W. Meijer, Jul 19 2013

MATHEMATICA

a[n_, k_] := Mod[Binomial[n, k]*Hypergeometric2F1[-k, k-n, -n, -1], 3]; Table[a[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, Jan 14 2014, after Johannes W. Meijer *)

CROSSREFS

Cf. A008288, A211312-A211315.

Sequence in context: A102552 A131341 A124034 * A085978 A141044 A064284

Adjacent sequences:  A211309 A211310 A211311 * A211313 A211314 A211315

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Apr 15 2012

STATUS

approved

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Last modified November 20 08:16 EST 2018. Contains 317385 sequences. (Running on oeis4.)