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A154919
Triangle, read by rows, T(n, k) = binomial(3*n, 2*k) + binomial(3*n, 2*(n-k)).
1
2, 4, 4, 16, 30, 16, 85, 162, 162, 85, 496, 990, 990, 990, 496, 3004, 6540, 6370, 6370, 6540, 3004, 18565, 43911, 46818, 37128, 46818, 43911, 18565, 116281, 294140, 358701, 257754, 257754, 358701, 294140, 116281, 735472, 1961532, 2714782, 2095852, 1470942, 2095852, 2714782, 1961532, 735472
OFFSET
0,1
COMMENTS
Row sums are: {2, 8, 62, 494, 3962, 31828, 255716, 2053752, 16486218, 132274304, 1060792742, ...}.
FORMULA
T(n, k) = binomial(3*n, 2*k) + binomial(3*n, 2*(n-k)).
EXAMPLE
Triangle begins as:
2;
4, 4;
16, 30, 16;
85, 162, 162, 85;
496, 990, 990, 990, 496;
3004, 6540, 6370, 6370, 6540, 3004;
18565, 43911, 46818, 37128, 46818, 43911, 18565;
MAPLE
b:=binomial; seq(seq( b(3*n, 2*k) + b(3*n, 2*(n-k)), k=0..n), n=0..10); # G. C. Greubel, Dec 02 2019
MATHEMATICA
Table[Binomial[3*n, 2*k] +Binomial[3*n, 2*(n-k)], {n, 0, 10}, {k, 0, n}]//Flatten (* modified by G. C. Greubel, Dec 02 2019 *)
PROG
(PARI) T(n, k) = my(b=binomia); b(3*n, 2*k) + b(3*n, 2*(n-k)); \\ G. C. Greubel, Dec 02 2019
(Magma) B:=Binomial; [B(3*n, 2*k) + B(3*n, 2*(n-k)): k in [0..n], n in [0..10]]; // G. C. Greubel, Dec 02 2019
(Sage) b=binomial; [[b(3*n, 2*k) + b(3*n, 2*(n-k)) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Dec 02 2019
(GAP) B:=Binomial;; Flat(List([0..10], n-> List([0..n], k-> B(3*n, 2*k) + B(3*n, 2*(n-k)) ))); # G. C. Greubel, Dec 02 2019
CROSSREFS
Sequence in context: A230874 A349452 A176739 * A019230 A298148 A088042
KEYWORD
nonn,tabl
AUTHOR
Roger L. Bagula, Jan 17 2009
EXTENSIONS
Edited by G. C. Greubel, Dec 02 2019
STATUS
approved