A338819 The entries in the rows of the n X n identity matrix, multiplied by the size of the matrix (n).

1, 2, 0, 0, 2, 3, 0, 0, 0, 3, 0, 0, 0, 3, 4, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4, 0, 0, 0, 0, 4, 5, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 5, 6, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 6, 7, 0

Offset

1,2

Links

Table of n, a(n) for n=1..93.

Example

For every identity matrix of size n starting with n=1, append n*(each entry of each row of the matrix), e.g., n=1 -> 1, n=2 -> 2,0,0,2, so the first 5 terms of the sequence are 1,2,0,0,2.

Prog

(Python)
import numpy as np
def n_id_sequence(iterations):
    sequence = []
    for i in range(1, iterations+1):
        matrix = i*(np.identity(i))
        for row in matrix:
            for entry in row:
                sequence.append(int(entry))
    return sequence

Crossrefs

Cf. A191747 (with 1's), A191748 (locations of nonzero terms), A056520 (start location of each matrix).

Sequence in context: A033747 A087611 A282133 * A153869 A128541 A122908

Adjacent sequences: A338816 A338817 A338818 * A338820 A338821 A338822

Keyword

nonn,easy

Author

Julia Zimmerman, Nov 10 2020

Status

approved