A118013 Triangle read by rows: T(n,k) = floor(n^2/k), 1<=k<=n.

1, 4, 2, 9, 4, 3, 16, 8, 5, 4, 25, 12, 8, 6, 5, 36, 18, 12, 9, 7, 6, 49, 24, 16, 12, 9, 8, 7, 64, 32, 21, 16, 12, 10, 9, 8, 81, 40, 27, 20, 16, 13, 11, 10, 9, 100, 50, 33, 25, 20, 16, 14, 12, 11, 10, 121, 60, 40, 30, 24, 20, 17, 15, 13, 12, 11, 144, 72, 48, 36, 28, 24, 20, 18, 16, 14

Offset

1,2

Comments

T(n,1) = A000290(n); T(n,n) = n;

T(n,2) = A007590(n) for n>1;

T(n,3) = A000212(n) for n>2;

T(n,4) = A002620(n) for n>3;

T(n,5) = A118015(n) for n>4;

T(n,6) = A056827(n) for n>5;

central terms give A008574: T(2*k-1,k) = 4*(k-1)+0^(k-1);

row sums give A118014.

Links

Reinhard Zumkeller, Rows n=1..100 of triangle, flattened

Example

Triangle begins:
1,
4, 2,
9, 4, 3,
16, 8, 5, 4,

Prog

(PARI) T(n, k)=n^2\k \\ Charles R Greathouse IV, Jan 15 2012
(Haskell)
a118013 n k = a118013_tabl !! (n-1) !! (k-1)
a118013_row n = map (div (n^2)) [1..n]
a118013_tabl = map a118013_row [1..]
-- Reinhard Zumkeller, Jan 22 2012

Crossrefs

Cf. A010766.

Sequence in context: A064421 A051494 A262025 * A157647 A194108 A091452

Adjacent sequences: A118010 A118011 A118012 * A118014 A118015 A118016

Keyword

nonn,easy,tabl

Author

Reinhard Zumkeller, Apr 10 2006

Status

approved