A331153 Triangle read by rows: T(n,k) (n>=k>=1) = round((n/k)*round(n/k)).

1, 4, 1, 9, 3, 1, 16, 4, 1, 1, 25, 8, 3, 1, 1, 36, 9, 4, 3, 1, 1, 49, 14, 5, 4, 1, 1, 1, 64, 16, 8, 4, 3, 1, 1, 1, 81, 23, 9, 5, 4, 3, 1, 1, 1, 100, 25, 10, 8, 4, 3, 1, 1, 1, 1, 121, 33, 15, 8, 4, 4, 3, 1, 1, 1, 1, 144, 36, 16, 9, 5, 4, 3, 3, 1, 1, 1, 1, 169, 46, 17, 10, 8, 4, 4, 3, 1, 1, 1, 1, 1

Offset

1,2

Links

Table of n, a(n) for n=1..91.

Robert J. McEliece and Herbert Taylor, Covering tori with squares, Journal of Combinatorial Theory, Series A 14.1 (1973): 119-124.

Example

Triangle begins:
1,
4, 1,
9, 3, 1,
16, 4, 1, 1,
25, 8, 3, 1, 1,
36, 9, 4, 3, 1, 1,
49, 14, 5, 4, 1, 1, 1,
64, 16, 8, 4, 3, 1, 1, 1,
81, 23, 9, 5, 4, 3, 1, 1, 1,
100, 25, 10, 8, 4, 3, 1, 1, 1, 1,
121, 33, 15, 8, 4, 4, 3, 1, 1, 1, 1,
144, 36, 16, 9, 5, 4, 3, 3, 1, 1, 1, 1,
169, 46, 17, 10, 8, 4, 4, 3, 1, 1, 1, 1, 1,
...

Crossrefs

Cf. A331145-A331154.

Sequence in context: A260253 A261981 A153265 * A331149 A331145 A339635

Adjacent sequences: A331150 A331151 A331152 * A331154 A331155 A331156

Keyword

nonn,tabl

Author

N. J. A. Sloane, Jan 14 2020

Status

approved