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A132918 Identity matrix with interpolated zeros. 1
1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Given A132918 = matrix M, then M * any sequence as a vector replaces alternate terms with zeros; e.g. M * [1,2,3,...] = [1,0,3,0,5,...]. M * (any infinite lower triangular matrix) replaces alternate rows with zeros; e.g. M * A007318 = (1; 0,0; 1,2,1; 0,0,0,0;...).

LINKS

Table of n, a(n) for n=1..29.

FORMULA

Identity matrix with interpolated zeros, such that the diagonal of an infinite lower triangular matrix = (1, 0, 1, 0, 1,...) with the rest zeros. a(n) = 1 if n = a hexagonal number, A000384: (1, 6, 15, 28, 45, 66,...); zero otherwise.

EXAMPLE

First few rows of the triangle are:

1;

0, 0;

0, 0, 1;

0, 0, 0, 0;

0, 0, 0, 0, 1;

...

CROSSREFS

Sequence in context: A015959 A014834 A015659 * A205809 A327153 A133943

Adjacent sequences:  A132915 A132916 A132917 * A132919 A132920 A132921

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Sep 05 2007

STATUS

approved

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Last modified October 23 17:37 EDT 2021. Contains 348215 sequences. (Running on oeis4.)