A121490 Rectangular array T by antidiagonals: T(n,k) = [y+1]^2-y^2, where y=n*sqrt(k) and [ ] denotes the floor function.

3, 2, 5, 1, 1, 7, 5, 4, 7, 9, 4, 9, 9, 4, 11, 3, 5, 13, 1, 14, 13, 2, 1, 4, 17, 6, 9, 15, 1, 8, 10, 1, 21, 13, 2, 17, 7, 4, 1, 4, 19, 25, 22, 16, 19, 6, 13, 9, 9, 19, 16, 29, 4, 7, 21, 5, 9, 19, 16, 21, 9, 11, 33, 13, 25, 23, 4, 5, 10, 25, 25, 4, 30, 4, 37, 24, 14, 25, 3, 1, 1, 9, 31, 1, 18, 16

Offset

1,1

Comments

(Row 1)=A080883; (Column 1)=A005408 except for initial term; (Column 2)=A087059; (Column 3)=A120865; (Column 4)=A016813 except for initial term; (Column 5)=A120867; Columns 1,4,9,16,25,... are arithmetic sequences; (Main diagonal)=A121489.

Links

Table of n, a(n) for n=1..86.

Formula

T(n,k) = [y+1]^2-y^2

Example

Northwest corner:
3 2 1 5 4
5 1 4 9 5
7 7 9 13 4
9 4 1 17 1

Crossrefs

Sequence in context: A291455 A248849 A172216 * A197293 A099643 A224344

Adjacent sequences: A121487 A121488 A121489 * A121491 A121492 A121493

Keyword

nonn,tabl

Author

Clark Kimberling, Aug 02 2006

Status

approved