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A144451 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. 1
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)
OFFSET

1,9

COMMENTS

Row sums are 1, 2, 2, 4, 3, 4, 4, 10, 5, -14, 6, 128, 7, -720, 8, 4630, 9, -30194, 10, ...

LINKS

Table of n, a(n) for n=1..55.

FORMULA

A(n,k) = A(n-2,k-1) - 2*A(n,k-1) + 1.

EXAMPLE

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;

MAPLE

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

MATHEMATICA

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]

CROSSREFS

Sequence in context: A276004 A133300 A178779 * A259287 A090464 A277967

Adjacent sequences:  A144448 A144449 A144450 * A144452 A144453 A144454

KEYWORD

tabl,sign,easy

AUTHOR

Roger L. Bagula and Gary W. Adamson, Oct 06 2008

STATUS

approved

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Last modified September 15 04:09 EDT 2019. Contains 327062 sequences. (Running on oeis4.)