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A135839 Triangle read by rows: starting with A138174, replace left border with (1, 1, 1, ...). 3
1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row sums = (1, 2, 2, 3, 3, 4, 4, 5, 5, ...).

LINKS

G. C. Greubel, Table of n, a(n) for the first 50 rows

FORMULA

Given A128174, replace left border with (1, 1, 1, ...). Triangle read by rows, odd rows = n terms of (1, 0, 1, ...); even rows = n terms of (1, 1, 0, 1, 0, 1, ...). By columns, leftmost column = (1, 1, 1, ...); all others = (1, 0, 1, 0, 1, ...).

T(n,1) = T(n,n) = 1, T(n,k) = (1 - (-1)^(n-k-1))/2. - G. C. Greubel,Dec 05 2016

EXAMPLE

First few rows of the triangle are:

1;

1, 1;

1, 0, 1;

1, 1, 0, 1;

1, 0, 1, 0, 1;

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

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

...

MATHEMATICA

T[1, 1] := 1; T[n_, 1] := 1; T[n_, n_] := 1; T[n_, k_] := (1 - (-1)^(n - k + 1))/2; Table[T[n, k], {n, 1, 10}, {k, 1, n}]//Flatten (* G. C. Greubel, Dec 05 2016 *)

CROSSREFS

Sequence in context: A103994 A051731 A304569 * A071022 A155076 A257196

Adjacent sequences:  A135836 A135837 A135838 * A135840 A135841 A135842

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Dec 01 2007

STATUS

approved

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Last modified April 19 08:34 EDT 2019. Contains 322241 sequences. (Running on oeis4.)