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A122950
Triangle T(n,k), 0 <= k <= n, read by rows, given by [0, 0, 1, -1, 0, 0, 0, 0, 0, 0, ...] DELTA [1, 1, -1, 0, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938.
19
1, 0, 1, 0, 0, 2, 0, 0, 1, 3, 0, 0, 0, 3, 5, 0, 0, 0, 1, 7, 8, 0, 0, 0, 0, 4, 15, 13, 0, 0, 0, 0, 1, 12, 30, 21, 0, 0, 0, 0, 0, 5, 31, 58, 34, 0, 0, 0, 0, 0, 1, 18, 73, 109, 55, 0, 0, 0, 0, 0, 0, 6, 54, 162, 201, 89, 0, 0, 0, 0, 0, 0, 1, 25, 145, 344, 365, 144, 0, 0, 0, 0, 0, 0, 0, 7, 85, 361, 707
OFFSET
0,6
COMMENTS
Skew triangle associated with the Fibonacci numbers.
LINKS
FORMULA
Sum_{k=0..n} T(n,k) = A011782(n).
Sum_{n>=k} T(n,k) = A001333(k).
T(n,k) = 0 if k < 0 or if k > n, T(0,0) = 1, T(2,1) = 0, T(n,k) = T(n-1,k-1) + T(n-2,k-1) + T(n-2,k-2).
T(n,n) = Fibonacci(n+1) = A000045(n+1).
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A011782(n), A133592(n), A133594(n), A133642(n), A133646(n), A133678(n), A133679(n), A133680(n), A133681(n) for x = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 respectively. - Philippe Deléham, Jan 03 2008
G.f.: (1-y*x^2)/(1-y*x-y*(y+1)*x^2). - Philippe Deléham, Nov 26 2011
EXAMPLE
Triangle begins:
1;
0, 1;
0, 0, 2;
0, 0, 1, 3;
0, 0, 0, 3, 5;
0, 0, 0, 1, 7, 8;
0, 0, 0, 0, 4, 15, 13;
0, 0, 0, 0, 1, 12, 30, 21;
0, 0, 0, 0, 0, 5, 31, 58, 34;
0, 0, 0, 0, 0, 1, 18, 73, 109, 55;
0, 0, 0, 0, 0, 0, 6, 54, 162, 201, 89;
0, 0, 0, 0, 0, 0, 1, 25, 145, 344, 365, 144;
0, 0, 0, 0, 0, 0, 0, 7, 85, 361, 707, 655, 233;
MATHEMATICA
T[0, 0] = T[1, 1] = 1; T[_, 0] = T[_, 1] = 0; T[n_, n_] := Fibonacci[n+1]; T[n_, k_] /; 0 <= k <= n := T[n, k] = T[n-1, k-1] + T[n-2, k-1] + T[n-2, k-2]; T[_, _] = 0;
Table[T[n, k], {n, 0, 12}, {k, 0, n}] // Flatten (* Jean-François Alcover, Nov 29 2018 *)
CROSSREFS
Cf. A055830 (another version).
Sequence in context: A350530 A258850 A182114 * A374766 A116489 A166373
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Oct 25 2006
STATUS
approved