A331149 Triangle read by rows: T(n,k) (n>=k>=1) = floor((n/k)*ceiling(n/k)).

1, 4, 1, 9, 3, 1, 16, 4, 2, 1, 25, 7, 3, 2, 1, 36, 9, 4, 3, 2, 1, 49, 14, 7, 3, 2, 2, 1, 64, 16, 8, 4, 3, 2, 2, 1, 81, 22, 9, 6, 3, 3, 2, 2, 1, 100, 25, 13, 7, 4, 3, 2, 2, 2, 1, 121, 33, 14, 8, 6, 3, 3, 2, 2, 2, 1, 144, 36, 16, 9, 7, 4, 3, 3, 2, 2, 2, 1, 169, 45, 21, 13, 7, 6, 3, 3, 2, 2, 2, 2, 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, 2, 1,
25, 7, 3, 2, 1,
36, 9, 4, 3, 2, 1,
49, 14, 7, 3, 2, 2, 1,
64, 16, 8, 4, 3, 2, 2, 1,
81, 22, 9, 6, 3, 3, 2, 2, 1,
100, 25, 13, 7, 4, 3, 2, 2, 2, 1,
121, 33, 14, 8, 6, 3, 3, 2, 2, 2, 1,
144, 36, 16, 9, 7, 4, 3, 3, 2, 2, 2, 1,
169, 45, 21, 13, 7, 6, 3, 3, 2, 2, 2, 2, 1,
...

Crossrefs

Cf. A331145-A331154.

Sequence in context: A261981 A153265 A331153 * A331145 A339635 A085691

Adjacent sequences: A331146 A331147 A331148 * A331150 A331151 A331152

Keyword

nonn,tabl

Author

N. J. A. Sloane, Jan 14 2020

Status

approved