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A123262 Fibonacci-tribonacci triangle. 0
0, 0, 1, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 3, 0, 0, 0, 0, 2, 5, 0, 0, 0, 0, 0, 5, 8, 0, 0, 0, 0, 0, 1, 10, 13, 0, 0, 0, 0, 0, 0, 3, 20, 21, 0, 0, 0, 0, 0, 0, 0, 9, 38, 34, 0, 0, 0, 0, 0, 0, 0, 1, 22, 71, 55, 0, 0, 0, 0, 0, 0, 0, 0, 4, 51, 130, 89, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14, 111, 235, 144 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,10

COMMENTS

Or, skew Jacobsthal-Lucas triangle, read by rows.

LINKS

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

FORMULA

T(n,k)=T(n-1,k-1)+T(n-2,k-2)+T(n-3,k-2), T(n,0)=0, T(1,1)=1, T(n,k)=0 if k<0 or if k>n . T(n,n)= Fibonacci(n)=A000045(n) . Sum_{k, 0<=k<=n}T(n,k)=A000073(n+1), tribonacci numbers . Sum_{n, n>=k}T(n,k)=A001045(k), Jacobsthal sequence.

EXAMPLE

Triangle begins:

.0;

.0, 1;

.0, 0, 1;

.0, 0, 0, 2;

.0, 0, 0, 1, 3;

.0, 0, 0, 0, 2, 5;

.0, 0, 0, 0, 0, 5, 8;

.0, 0, 0, 0, 0, 1, 10, 13;

.0, 0, 0, 0, 0, 0, 3, 20, 21;

.0, 0, 0, 0, 0, 0, 0, 9, 38, 34;

.0, 0, 0, 0, 0, 0, 0, 1, 22, 71, 55;

.0, 0, 0, 0, 0, 0, 0, 0, 4, 51, 130, 89;

.0, 0, 0, 0, 0, 0, 0, 0, 0, 14, 111, 235, 144;

CROSSREFS

Cf. A037027.

Sequence in context: A296167 A244233 A227345 * A191906 A187080 A301342

Adjacent sequences:  A123259 A123260 A123261 * A123263 A123264 A123265

KEYWORD

nonn,tabl

AUTHOR

Philippe Deléham, Nov 06 2006

STATUS

approved

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Last modified September 18 04:33 EDT 2020. Contains 337165 sequences. (Running on oeis4.)