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A173742
Triangle T(n,k) = binomial(n,k) + 6 with T(n,0) = T(n,n) = 1 for n >= 0, read by rows.
4
1, 1, 1, 1, 8, 1, 1, 9, 9, 1, 1, 10, 12, 10, 1, 1, 11, 16, 16, 11, 1, 1, 12, 21, 26, 21, 12, 1, 1, 13, 27, 41, 41, 27, 13, 1, 1, 14, 34, 62, 76, 62, 34, 14, 1, 1, 15, 42, 90, 132, 132, 90, 42, 15, 1, 1, 16, 51, 126, 216, 258, 216, 126, 51, 16, 1, 1, 17, 61, 171, 336, 468, 468, 336, 171, 61, 17, 1
OFFSET
0,5
COMMENTS
For n >= 1, row n sums to A131520(n) + A008586(n).
FORMULA
From Franck Maminirina Ramaharo, Dec 09 2018: (Start)
T(n,k) = A007318(n,k) + 6*(1 - A103451(n,k)).
T(n,k) = 7*A007318(n,k) - 6*A132044(n,k).
n-th row polynomial is 3*(1 - (-1)^(2^n)) + (1 + x)^n + 6*(x - x^n)/(1 - x).
G.f.: (1 - (1 + x)*y + 7*x*y^2 - 6*(x + x^2)*y^3)/((1 - y)*(1 - x*y)*(1 - y - x*y)).
E.g.f.: (6 - 6*x + 6*x*exp(y) - 6*exp(x*y) + (1 - x)*exp((1 + x)*y))/(1 - x). (End)
Sum_{k=0..n} T(n, k) = 2^n + 6*n - 6 + 6*[n=0]. - G. C. Greubel, Feb 13 2021
EXAMPLE
Triangle begins:
1;
1, 1;
1, 8, 1;
1, 9, 9, 1;
1, 10, 12, 10, 1;
1, 11, 16, 16, 11, 1;
1, 12, 21, 26, 21, 12, 1;
1, 13, 27, 41, 41, 27, 13, 1;
1, 14, 34, 62, 76, 62, 34, 14, 1;
1, 15, 42, 90, 132, 132, 90, 42, 15, 1;
1, 16, 51, 126, 216, 258, 216, 126, 51, 16, 1;
...
MATHEMATICA
T[n_, m_] = Binomial[n, m] + 6*If[m*(n - m) > 0, 1, 0];
Flatten[Table[T[n, m], {n, 0, 10}, {m, 0, n}]]
PROG
(Maxima) T(n, k) := if k = 0 or k = n then 1 else binomial(n, k) + 6$
create_list(T(n, k), n, 0, 12, k, 0, n); /* Franck Maminirina Ramaharo, Dec 09 2018 */
(Sage)
def T(n, k): return 1 if (k==0 or k==n) else binomial(n, k) + 6
flatten([[T(n, k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 13 2021
(Magma)
T:= func< n, k | k eq 0 or k eq n select 1 else Binomial(n, k) +6 >;
[T(n, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 13 2021
CROSSREFS
KEYWORD
nonn,tabl,easy
AUTHOR
Roger L. Bagula, Feb 23 2010
EXTENSIONS
Edited and name clarified by Franck Maminirina Ramaharo, Dec 09 2018
STATUS
approved