A331147 Triangle read by rows: T(n,k) (n>=k>=1) = floor((n/k)*floor(n/k)).

1, 4, 1, 9, 1, 1, 16, 4, 1, 1, 25, 5, 1, 1, 1, 36, 9, 4, 1, 1, 1, 49, 10, 4, 1, 1, 1, 1, 64, 16, 5, 4, 1, 1, 1, 1, 81, 18, 9, 4, 1, 1, 1, 1, 1, 100, 25, 10, 5, 4, 1, 1, 1, 1, 1, 121, 27, 11, 5, 4, 1, 1, 1, 1, 1, 1, 144, 36, 16, 9, 4, 4, 1, 1, 1, 1, 1, 1, 169, 39, 17, 9, 5, 4, 1, 1, 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, 1, 1,
16, 4, 1, 1,
25, 5, 1, 1, 1,
36, 9, 4, 1, 1, 1,
49, 10, 4, 1, 1, 1, 1,
64, 16, 5, 4, 1, 1, 1, 1,
81, 18, 9, 4, 1, 1, 1, 1, 1,
100, 25, 10, 5, 4, 1, 1, 1, 1, 1,
121, 27, 11, 5, 4, 1, 1, 1, 1, 1, 1,
144, 36, 16, 9, 4, 4, 1, 1, 1, 1, 1, 1,
169, 39, 17, 9, 5, 4, 1, 1, 1, 1, 1, 1, 1,
...

Crossrefs

Cf. A331145-A331154.

Sequence in context: A364016 A143469 A360610 * A208508 A123726 A323600

Adjacent sequences: A331144 A331145 A331146 * A331148 A331149 A331150

Keyword

nonn,tabl

Author

N. J. A. Sloane, Jan 14 2020

Status

approved