A126696 Tenth-squares: floor(n/10)*ceiling(n/10).

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 6, 6, 6, 6, 6, 6, 6, 6, 6, 9, 12, 12, 12, 12, 12, 12, 12, 12, 12, 16, 20, 20, 20, 20, 20, 20, 20, 20, 20, 25, 30, 30, 30, 30, 30, 30, 30, 30, 30, 36, 42, 42, 42, 42, 42, 42, 42, 42, 42, 49, 56, 56, 56, 56, 56, 56, 56, 56, 56

Offset

0,12

Links

Table of n, a(n) for n=0..79.

Formula

Equivalently, floor(n^2/100).

Mathematica

f[n_]:=Module[{c=n/10}, Floor[c]Ceiling[c]]; f[Range[0, 90]] (* Harvey P. Dale, Apr 04 2011 *)

Prog

(Magma) [ Floor(n/10)*Ceiling(n/10) : n in [0..100]];

Crossrefs

Cf. A002620, A024206, A072280, A002984, A007590, A000212, A118015, A056827, A118013.

Sequence in context: A391788 A032574 A058515 * A244464 A250201 A252375

Adjacent sequences: A126693 A126694 A126695 * A126697 A126698 A126699

Keyword

easy,nonn

Author

Jonathan Vos Post, May 27 2007

Status

approved