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A154229
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Triangle T(n, k) = T(n-1, k) + T(n-1, k-1) + ((n+1)*(n+2)/2)^2*T(n-2, k-1), read by rows.
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6
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1, 1, 1, 1, 38, 1, 1, 139, 139, 1, 1, 365, 8828, 365, 1, 1, 807, 70492, 70492, 807, 1, 1, 1592, 357459, 7062136, 357459, 1592, 1, 1, 2889, 1404923, 98777227, 98777227, 1404923, 2889, 1, 1, 4915, 4631612, 824036625, 14498379854, 824036625, 4631612, 4915, 1
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OFFSET
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0,5
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COMMENTS
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Row sums are: {1, 2, 40, 280, 9560, 142600, 7780240, 200370080, 16155726160, ...}.
The row sums of this class of sequences (see cross-references) is given by the following. Let S(n) be the row sum then S(n) = 2*S(n-1) + f(n)*S(n-2) for a given f(n). For this sequence f(n) = binomial(n+2, 2)^2 = A000537(n+1). - G. C. Greubel, Mar 02 2021
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LINKS
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FORMULA
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T(n, k) = T(n-1, k) + T(n-1, k-1) + ((n+1)*(n+2)/2)^2*T(n-2, k-1) with T(n, 0) = T(n, n) = 1.
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EXAMPLE
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Triangle begins as:
1;
1, 1;
1, 38, 1;
1, 139, 139, 1;
1, 365, 8828, 365, 1;
1, 807, 70492, 70492, 807, 1;
1, 1592, 357459, 7062136, 357459, 1592, 1;
1, 2889, 1404923, 98777227, 98777227, 1404923, 2889, 1;
1, 4915, 4631612, 824036625, 14498379854, 824036625, 4631612, 4915, 1;
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MAPLE
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T:= proc(n, k) option remember;
if k=0 or k=n then 1
else T(n-1, k) + T(n-1, k-1) + binomial(n+2, 2)^2*T(n-2, k-1)
fi; end:
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MATHEMATICA
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T[n_, k_]:= T[n, k]= If[k==0 || k==n, 1, T[n-1, k] + T[n-1, k-1] + Binomial[n+2, 2]^2*T[n-2, k-1]];
Table[T[n, k], {n, 0, 12}, {k, 0, n}]//Flatten (* modified by G. C. Greubel, Mar 02 2021 *)
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PROG
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(Sage)
def f(n): return binomial(n+2, 2)^2
def T(n, k):
if (k==0 or k==n): return 1
else: return T(n-1, k) + T(n-1, k-1) + f(n)*T(n-2, k-1)
flatten([[T(n, k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 02 2021
(Magma)
f:= func< n | Binomial(n+2, 2)^2 >;
function T(n, k)
if k eq 0 or k eq n then return 1;
else return T(n-1, k) + T(n-1, k-1) + f(n)*T(n-2, k-1);
end if; return T;
end function;
[T(n, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Mar 02 2021
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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