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A108358 A mod 2 triangle based on floor((n+2)/2). 2
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Row sums are A108355. Diagonal sums are A108356.

LINKS

Table of n, a(n) for n=0..104.

FORMULA

Number triangle T(n, k)=(sum{j=0..n-k, C(k, j)C(n-j, k)*floor((j+2)/2)} mod 2); Column k has g.f. x^k(1+x(mod(a(k+2), 4)))/(1-x^a(k)) where a(n)=-3cos(pi*n/2)/2-3sin(pi*n/2)/2+5/2=(1, 1, 4, 4, 1, 1, 4, 4, ...). T(n, k)=A108359(n, k) mod 2.

EXAMPLE

Rows begin

1;

1,1;

1,1,1;

1,1,1,1;

1,1,0,1,1;

1,1,0,0,1,1;

1,1,1,0,1,1,1;

1,1,1,1,1,1,1,1;

CROSSREFS

Sequence in context: A131217 A105567 A114213 * A267959 A144384 A144475

Adjacent sequences:  A108355 A108356 A108357 * A108359 A108360 A108361

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, May 31 2005

STATUS

approved

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Last modified October 22 16:15 EDT 2021. Contains 348174 sequences. (Running on oeis4.)