OFFSET
0,4
COMMENTS
LINKS
Indranil Ghosh, Rows 0..100, flattened
FORMULA
Riordan array ((1-3x)/(1-4x+x^2), x(1-x)/(1-4x+x^2)).
T(n,k) = 4*T(n-1,k) + T(n-1,k-1) - T(n-2,k) - T(n-2,k-1), n > 1. - Philippe Deléham, Feb 13 2012
G.f.: (1-3*x)/(1-4*x+(1+y)*x^2-y*x). - Philippe Deléham, Feb 13 2012
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A001835(n), A147722(n), A084120(n) for x = -1, 0, 1, 2 respectively. - Philippe Deléham, Feb 13 2012
EXAMPLE
Triangle begins
1;
1, 1;
3, 4, 1;
11, 17, 7, 1;
41, 72, 40, 10, 1;
153, 301, 208, 72, 13, 1;
MATHEMATICA
nmax=9; Flatten[CoefficientList[Series[CoefficientList[Series[(1 - 3*x)/(1 - 4*x + (1 + y)*x^2 - y*x), {x, 0, nmax}], x], {y, 0, nmax}], y]] (* Indranil Ghosh, Mar 10 2017, after Philippe Deléham *)
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Nov 11 2008
STATUS
approved