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A144451
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Triangle A(n,k) read by rows: A(n,1)=A(n,n)=1 and A(n,k) = A(n-2,k-1) - 2*A(n,k-1) + 1 for 1<k<n.
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1
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1, 1, 1, 1, 0, 1, 1, 0, 2, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 2, -3, 8, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, -4, 17, -32, 1
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,9
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COMMENTS
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Row sums are 1, 2, 2, 4, 3, 4, 4, 10, 5, -14, 6, 128, 7, -720, 8, 4630, 9, -30194, 10, ...
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LINKS
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Table of n, a(n) for n=1..55.
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FORMULA
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A(n,k) = A(n-2,k-1) - 2*A(n,k-1) + 1.
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EXAMPLE
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1;
1, 1;
1, 0, 1;
1, 0, 2, 1;
1, 0, 1, 0, 1;
1, 0, 1, 1, 0, 1;
1, 0, 1, 0, 1, 0, 1;
1, 0, 1, 0, 2, -3, 8, 1;
1, 0, 1, 0, 1, 0, 1, 0, 1;
1, 0, 1, 0, 1, 1, -4, 17, -32, 1;
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MAPLE
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A144451 := proc(n, k)
option remember;
if k < 1 or k > n then
0 ;
elif n = 1 or n=k then
1;
else
procname(n-2, k-1)-2*procname(n, k-1)+1 ;
end if;
end proc: # R. J. Mathar, Jul 21 2015
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MATHEMATICA
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A[n_, 1] := 1; A[n_, n_] := 1; A[n_, k_] := A[n, k] = A[n - 2, k - 1] - 2*A[n, k - 1] + 1; a = Table[A[n, k], {n, 10}, {k, n}]; Flatten[a]
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CROSSREFS
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Sequence in context: A133300 A337101 A178779 * A259287 A342592 A090464
Adjacent sequences: A144448 A144449 A144450 * A144452 A144453 A144454
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KEYWORD
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tabl,sign,easy
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AUTHOR
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Roger L. Bagula and Gary W. Adamson, Oct 06 2008
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STATUS
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approved
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