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A208153 Convolution triangle based on A006053. 1

%I #11 Mar 10 2017 07:57:48

%S 1,1,1,3,2,1,4,7,3,1,9,14,12,4,1,14,35,31,18,5,1,28,70,87,56,25,6,1,

%T 47,154,207,175,90,33,7,1,89,306,504,476,310,134,42,8,1,155,633,1137,

%U 1274,941,504,189,52,9,1

%N Convolution triangle based on A006053.

%C Riordan array (1/(1-x-2*x^2+x^3), x/(1-x-2*x^2+x^3).

%C Subtriangle of triangle given by (0, 1, 2, -5/2, 1/10, 2/5, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.

%C Diagonal sums are A125691(n).

%C Row sums are A001654(n+1).

%C Mirror image of triangle in A188107.

%H Indranil Ghosh, <a href="/A208153/b208153.txt">Rows 1..100, flattened</a>

%F T(n,k) = T(n-1,k-1) + T(n-1,k) + 2*T(n-2,k) - T(n-3,k).

%F G.f.: 1/(1-x-2*x^2+x^3-y*x).

%F Sum_{k, k>=0} T(n-2*k,k) = A001045(n+1).

%F Sum_{k, 0<=k<=n} T(n,k)*x^k = (-1)^n*A008346(n), A006053(n+2), A001654(n+1) for x = -1, 0, 1 respectively.

%e Triangle begins :

%e 1

%e 1, 1

%e 3, 2, 1

%e 4, 7, 3, 1

%e 9, 14, 12, 4, 1

%e 14, 35, 31, 18, 5, 1

%e Triangle (0, 1 ,2, -5/2, 1/10, 2/5, 0, 0,...) DELTA (1, 0, 0, 0,...) begins :

%e 1

%e 0, 1

%e 0, 1, 1

%e 0, 3, 2, 1

%e 0, 4, 7, 3, 1

%e 0, 9, 14, 12, 4, 1

%e 0, 14, 35, 31, 18, 5, 1

%t nmax=9; Flatten[CoefficientList[Series[CoefficientList[Series[1/(1 - x - 2*x^2 + x^3 - y*x), {x, 0, nmax}], x], {y, 0, nmax}], y]] (* _Indranil Ghosh_, Mar 10 2017 *)

%Y Cf. A006053, A000012, A000027, A055998

%K easy,nonn,tabl

%O 0,4

%A _Philippe Deléham_, Feb 24 2012

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)