login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A156917
General q-Narayana triangle sequence: T(n, k) = Product_{j=0..2} ( q_binomial(n+j, j+k, 3)/q_binomial(n+j-k, j, 3) ).
3
1, 1, 1, 1, 40, 1, 1, 1210, 1210, 1, 1, 33880, 1024870, 33880, 1, 1, 925771, 784128037, 784128037, 925771, 1, 1, 25095280, 580812061522, 16262737722616, 580812061522, 25095280, 1, 1, 678468820, 425659125229240, 325671796712891524
OFFSET
0,5
COMMENTS
Row sums are: {1, 2, 42, 2422, 1092632, 1570107618, 17424412036222, 652194913033179170, 189060566695044668933610, ...}.
FORMULA
T(n, k) = Product_{j=0..2} ( q_binomial(n+j, j+k, 3)/q_binomial(n+j-k, j, 3) ). - G. C. Greubel, May 22 2019
EXAMPLE
Triangle begins as:
1;
1, 1;
1, 40, 1;
1, 1210, 1210, 1;
1, 33880, 1024870, 33880, 1;
1, 925771, 784128037, 784128037, 925771, 1;
1, 25095280, 580812061522, 16262737722616, 580812061522, 25095280, 1;
MATHEMATICA
(* First Program *)t[n_, m_]:= If[m==0, n!, Product[Sum[(m+1)^i, {i, 0, k-1}], {k, 1, n}]];
b[n_, k_, m_]:= If[n==0, 1, t[n, m]/(t[k, m]*t[n-k, m])];
c[n_, l_, m_]:= Product[b[n+k, l+k, 2]/b[n-l+k, k, 2], {k, 0, m}];
Table[c[n, k, 2], {n, 0, 10}, {k, 0, n}]//Flatten(* Second Program *)
T[n_, k_]:= Product[QBinomial[n+j, j+k, 3]/QBinomial[n+j-k, j, 3], {j, 0, 2}];
Table[T[n, k], {n, 0, 5}, {k, 0, n}]//Flatten (* G. C. Greubel, May 22 2019 *)
PROG
(PARI)
b(n, k, q) = prod(j=1, k, (1-q^(n-j+1))/(1-q^j));
T(n, k) = prod(j=0, 2, b(n+j, j+k, 3)/b(n-k+j, j, 3));
for(n=0, 12, for(k=0, n, print1(T(n, k), ", "))) \\ G. C. Greubel, May 22 2019
(Magma)
B:= func< n, k, q | (&*[(1-q^(n-j+1))/(1-q^j): j in [1..k]]) >;
T:= func< n, k | k eq 0 select 1 else B(n, k, 3)*(&*[B(n+j, j+k, 3)/B(n-k+j, j, 3): j in [1..2]]) >;
[[T(n, k) : k in [0..n]]: n in [0..12]]; // G. C. Greubel, May 22 2019
(Sage)
def T(n, k): return product((q_binomial(n+j, j+k, 3)/q_binomial(n+j-k, j, 3)) for j in (0..2))
[[T(n, k) for k in (0..n)] for n in (0..12)] # G. C. Greubel, May 22 2019
CROSSREFS
Cf. A001263, A156916, this sequence, A156939.
Sequence in context: A013375 A013419 A013420 * A176644 A329337 A078084
KEYWORD
nonn,tabl
AUTHOR
Roger L. Bagula, Feb 18 2009
EXTENSIONS
Edited by G. C. Greubel, May 22 2019
STATUS
approved