OFFSET
0,1
FORMULA
From R. J. Mathar, Jun 12 2008: (Start)
T(n,k) = A007318(n,k), 0 <= k < n-1.
T(n,k) = A007318(n,k)+1, n-1 <= k <= n.
Sum_{k=0..n} T(n,k) = A133140(n). (End)
EXAMPLE
Triangle T(n,k) begins:
n/k 0 1 2 3 4 5 6 7 8 9 10 11 12
0: 2
1: 2 2
2: 1 3 2
3: 1 3 4 2
4: 1 4 6 5 2
5: 1 5 10 10 6 2
6: 1 6 15 20 15 7 2
7: 1 7 21 35 35 21 8 2
8: 1 8 28 56 70 56 28 9 2
9: 1 9 36 84 126 126 84 36 10 2
10: 1 10 45 120 210 252 210 120 45 11 2
11: 1 11 55 165 330 462 462 330 165 55 12 2
12: 1 12 66 220 495 792 924 792 495 220 66 13 2
... - Franck Maminirina Ramaharo, May 18 2018
MATHEMATICA
q[n_] := (1+x)*((1+x)^(n-1) + x^(n-1)); t[n_, k_] := Coefficient[q[n], x, k]; Table[t[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Dec 16 2013 *)
PROG
(Maxima)
Q(n, x) := (1 + x)*((1 + x)^(n - 1) + x^(n - 1))$
t(n, k) := ratcoef(expand(Q(n, x)), x, k)$
for n:0 thru 20 do print(makelist(t(n, k), k, 0, n)); /* Franck Maminirina Ramaharo, May 18 2018 */
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Paul Curtz, Sep 21 2007
EXTENSIONS
Edited by R. J. Mathar, Jun 12 2008
STATUS
approved