A059284 Right edge of triangle in A059283.

1, 1, 3, 11, 47, 219, 1081, 5557, 29439, 159611, 881405, 4940385, 28035205, 160751005, 929923395, 5420717819, 31809479855, 187757573787, 1114012352029, 6640357243537, 39746256802185, 238796968208537, 1439587364576015

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Formula

G.f.: -(-2+(-3*w^2-6*w+1)^(1/2))/(1+w)^2.

Mathematica

T[0, 0] = 1; T[n_, 0] = 0; T[n_, k_] /; 0 <= k <= n := T[n, k] = T[n, k - 1] + T[n - 1, k - 1] + T[n - 1, k] + T[n - 2, k - 1]; T[_, _] = 0; Table[T[n, n], {n, 0, 25}] (* G. C. Greubel, Jan 04 2016 *)

Crossrefs

Cf. A059283, A059226.

Sequence in context: A308227 A247313 A262607 * A118927 A217216 A301409

Adjacent sequences: A059281 A059282 A059283 * A059285 A059286 A059287

Keyword

nonn

Author

N. J. A. Sloane, Jan 24 2001

Status

approved