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A086461 Symmetric version of square array A086460. 0
1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 4, 3, 1, 1, 4, 6, 6, 4, 1, 1, 5, 8, 9, 8, 5, 1, 1, 6, 10, 12, 12, 10, 6, 1, 1, 7, 12, 15, 16, 15, 12, 7, 1, 1, 8, 14, 18, 20, 20, 18, 14, 8, 1, 1, 9, 16, 21, 24, 25, 24, 21, 16, 9, 1, 1, 10, 18, 24, 28, 30, 30, 28, 24, 18, 10, 1, 1, 11, 20, 27, 32, 35, 36 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,8

COMMENTS

Rows include A028310, A004277, A008486, A008574, A008706, A008458. Main diagonal is n^2+0^n (A000290, preceded by extra 1).

LINKS

Table of n, a(n) for n=0..84.

FORMULA

T(0, k)=T(n, 0)=1, T(n, k)=nk+0^n, n, k>0

Alternatively, triangle read by rows with formula t(n,m)=If[n == 0 || n == m || m == 0, 1, n - m]*If[n == m || n == 0 || m == 0, 1, m]. - Roger L. Bagula, Sep 06 2008

EXAMPLE

Rows begin

1 1 1 1 1 ...

1 1 2 3 4 ...

1 2 4 6 8 ...

1 3 6 9 12 ...

1 4 8 12 16 ...

As a triangle:

{1},

{1, 1},

{1, 1, 1},

{1, 2, 2, 1},

{1, 3, 4, 3, 1},

{1, 4, 6, 6, 4, 1},

{1, 5, 8, 9, 8, 5, 1},

{1, 6, 10, 12, 12, 10, 6, 1},

{1, 7, 12, 15, 16, 15, 12, 7, 1},

{1, 8, 14, 18, 20, 20, 18, 14, 8, 1},

{1, 9, 16, 21, 24, 25, 24, 21, 16, 9, 1}

MATHEMATICA

t[n_, m_] = If[ n == 0 || n == m || m == 0, 1, n - m]*If[n == m || n == 0 || m == 0, 1, m]; Table[Table[t[n, m], {m, 0, n}], {n, 0, 10}]; Flatten[%] - Roger L. Bagula, Sep 06 2008

CROSSREFS

Sequence in context: A050935 A104769 A078013 * A047089 A122218 A072405

Adjacent sequences:  A086458 A086459 A086460 * A086462 A086463 A086464

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, Jul 21 2003

STATUS

approved

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Last modified November 21 14:12 EST 2014. Contains 249779 sequences.