OFFSET
0,5
COMMENTS
May be read as a symmetric triangular (T(n,k) = T(n,n-k); k=0,...,n; n=0,1,...) or square array (A(n,r) = A(r,n) = T(n+r,r), read by antidiagonals). The diagonals of the former, resp. rows (or columns) of the latter, are: A000012 (all 1's), A015000 (q-integers for q=-13), A015265 (k=2), A015286 (k=3), A015303 (k=4), A015321 (k=5), A015337 (k=6), A015355 (k=7), A015370 (k=8), A015385 (k=9), A015402 (k=10), A015422 (k=11), A015438 (k=12). - M. F. Hasler, Nov 04 2012
LINKS
FORMULA
As a triangle, T(n, k) = Product_{i=1..k} ((-13)^(1+n-i)-1)/((-13)^i-1), with 0 <= k <= n = 0,1,2,...
EXAMPLE
The square array looks as follows:
1 1 1 1 1 1 ...
1 -12 157 -2040 26521 -344772 ...
1 157 26690 4508570 761974851 128773405047 ...
1 -2040 4508570 -9900819720 21752862899691 ...
1 26521 761974851 21752862899691 621305270140974342 ...
1 -344772 128773405047 -47790911017216080 17745052029585350965782 ...
(...)
MATHEMATICA
Flatten[Table[QBinomial[x, y, -13], {x, 0, 10}, {y, 0, x}]] (* Harvey P. Dale, Jul 12 2014 *)
PROG
(PARI) A015129(n, r, q=-13)=prod(i=1, r, (q^(1+n-i+r)-1)/(q^i-1)) \\ (Indexing is that of the square array: n, r=0, 1, 2, ...) - M. F. Hasler, Nov 03 2012
(Magma)
qBinomial:= func< n, k, q | k eq 0 select 1 else (&*[(1 -q^(n-j+1))/(1 -q^j): j in [1..k]]) >;
[qBinomial(n, k, -13): k in [0..n], n in [0..10]]; // A015129 // G. C. Greubel, Dec 01 2021
(Sage) flatten([[q_binomial(n, k, -13) for k in (0..n)] for n in (0..10)]) # G. C. Greubel, Dec 01 2021
CROSSREFS
Cf. analog triangles for other negative q=-2,...,-15: A015109 (q=-2), A015110 (q=-3), A015112 (q=-4), A015113 (q=-5), A015116 (q=-6), A015117 (q=-7), A015118 (q=-8), A015121 (q=-9), A015123 (q=-10), A015124 (q=-11), A015125 (q=-12), A015132 (q=-14), A015133 (q=-15). - M. F. Hasler, Nov 04 2012
Cf. analog triangles for positive q=2,...,24: A022166 (q=2), A022167 (q=3), A022168 (q=4), A022169 (q=5), A022170 (q=6), A022171 (q=7), A022172 (q=8), A022173 (q=9), A022174 (q=10), A022175 (q=11), A022176 (q=12), A022177 (q=13), A022178 (q=14), A022179 (q=15), A022180 (q=16), A022181 (q=17), A022182 (q=18), A022183 (q=19), A022184 (q=20), A022185 (q=21), A022186 (q=22), A022187 (q=23), A022188 (q=24). - M. F. Hasler, Nov 05 2012
KEYWORD
AUTHOR
STATUS
approved