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A306376
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Sum of the 2 X 2 minors in the n X n Pascal matrix.
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3
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0, 0, 1, 7, 34, 144, 574, 2226, 8533, 32587, 124453, 476145, 1826175, 7022379, 27072487, 104614863, 405122290, 1571859864, 6109296442, 23781666198, 92704406320, 361832294964, 1413879679672, 5530590849168, 21654384302110, 84859670743770, 332818903663390
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OFFSET
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0,4
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LINKS
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FORMULA
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G.f.: -1/(2*(x-1))*(1/(2*x-1)+1/sqrt(1-4*x)).
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MAPLE
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a:= proc(n) option remember; `if`(n<3, (n-1)*n/2,
((7*n^2-16*n+6)*a(n-1)-2*(7*n^2-17*n+9)*a(n-2)+
4*(n-1)*(2*n-3)*a(n-3))/(n*(n-2)))
end:
seq(a(n), n=0..30);
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MATHEMATICA
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a[n_] := a[n] = If[n < 3, (n-1)n/2,
((7n^2 - 16n + 6) a[n-1] - 2(7n^2 - 17n + 9) a[n-2] +
4(n-1)(2n-3) a[n-3])/(n(n-2))];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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