|
|
A055830
|
|
Triangle T read by rows: diagonal differences of triangle A037027.
|
|
31
|
|
|
1, 1, 0, 2, 1, 0, 3, 3, 1, 0, 5, 7, 4, 1, 0, 8, 15, 12, 5, 1, 0, 13, 30, 31, 18, 6, 1, 0, 21, 58, 73, 54, 25, 7, 1, 0, 34, 109, 162, 145, 85, 33, 8, 1, 0, 55, 201, 344, 361, 255, 125, 42, 9, 1, 0, 89, 365, 707, 850, 701, 413, 175, 52, 10, 1, 0, 144, 655, 1416, 1918, 1806, 1239, 630, 236, 63, 11, 1, 0
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,4
|
|
COMMENTS
|
Or, coefficients of a generalized Lucas-Pell polynomial read by rows. - Philippe Deléham, Nov 05 2006
|
|
LINKS
|
|
|
FORMULA
|
G.f.: (1-y*z) / (1-y*(1+y+z)).
T(i, j) = R(i-j, j), where R(0, 0)=1, R(0, j)=0 for j >= 1, R(1, j)=1 for j >= 0, R(i, j) = Sum_{k=0..j} (R(i-2, k) + R(i-1, k)) for i >= 1, j >= 1.
Sum_{k=0..n} x^k*T(n,k) = A039834(n-2), A000012(n), A000045(n+1), A001333(n), A003688(n), A015448(n), A015449(n), A015451(n), A015453(n), A015454(n), A015455(n), A015456(n), A015457(n) for x= -2,-1,0,1,2,3,4,5,6,7,8,9,10. - Philippe Deléham, Oct 22 2006
Triangle T(n,k), 0 <= k <= n, given by [1, 1, -1, 0, 0, 0, 0, 0, ...] DELTA [0, 1, 0, 0, 0, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938. - Philippe Deléham, Nov 05 2006
T(n,0) = Fibonacci(n+1) = A000045(n+1). Sum_{k=0..n} T(n,k) = A001333(n). T(n,k)=0 if k > n or if k < 0, T(0,0)=1, T(1,1)=0, T(n,k) = T(n-1,k-1) + T(n-1,k) + T(n-2,k). - Philippe Deléham, Nov 05 2006
|
|
EXAMPLE
|
Triangle begins:
1
1, 0
2, 1, 0
3, 3, 1, 0
5, 7, 4, 1, 0
8, 15, 12, 5, 1, 0
13, 30, 31, 18, 6, 1, 0
21, 58, 73, 54, 25, 7, 1, 0
34, 109, 162, 145, 85, 33, 8, 1, 0
55, 201, 344, 361, 255, 125, 42, 9, 1, 0
...
|
|
MAPLE
|
with(combinat);
T:= proc(n, k) option remember;
if k<0 or k>n then 0
elif k=0 then fibonacci(n+1)
elif n=1 and k=1 then 0
else T(n-1, k-1) + T(n-1, k) + T(n-2, k)
fi; end:
|
|
MATHEMATICA
|
T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[k==0, Fibonacci[n+1], If[n==1 && k==1, 0, T[n-1, k-1] + T[n-1, k] + T[n-2, k]]]]; Table[T[n, k], {n, 0, 12}, {k, 0, n}]//Flatten (* G. C. Greubel, Dec 19 2017 *)
|
|
PROG
|
(PARI) T(n, k) = if(k<0 || k>n, 0, if(k==0, fibonacci(n+1), if(n==1 && k==1, 0, T(n-1, k-1) + T(n-1, k) + T(n-2, k) )));
for(n=0, 12, for(k=0, n, print1(T(n, k), ", "))) \\ G. C. Greubel, Jan 21 2020
(Magma)
function T(n, k)
if k lt 0 or k gt n then return 0;
elif k eq 0 then return Fibonacci(n+1);
elif n eq 1 and k eq 1 then return 0;
else return T(n-1, k-1) + T(n-1, k) + T(n-2, k);
end if; return T; end function;
[T(n, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jan 21 2020
(Sage)
@CachedFunction
def T(n, k):
if (k<0 or k>n): return 0
elif (k==0): return fibonacci(n+1)
elif (n==1 and k==1): return 0
else: return T(n-1, k-1) + T(n-1, k) + T(n-2, k)
[[T(n, k) for k in (0..n)] for n in (0..12)] # G. C. Greubel, Jan 21 2020
|
|
CROSSREFS
|
Row sums: A001333 (numerators of continued fraction convergents to sqrt(2)).
|
|
KEYWORD
|
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|