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A168281
Triangle T(n,m) = 2*(min(n - m + 1, m))^2 read by rows.
4
2, 2, 2, 2, 8, 2, 2, 8, 8, 2, 2, 8, 18, 8, 2, 2, 8, 18, 18, 8, 2, 2, 8, 18, 32, 18, 8, 2, 2, 8, 18, 32, 32, 18, 8, 2, 2, 8, 18, 32, 50, 32, 18, 8, 2, 2, 8, 18, 32, 50, 50, 32, 18, 8, 2, 2, 8, 18, 32, 50, 72, 50, 32, 18, 8, 2, 2, 8, 18, 32, 50, 72, 72, 50, 32, 18, 8, 2, 2, 8, 18, 32, 50, 72, 98, 72
OFFSET
1,1
COMMENTS
Row sums are A099956(n-1) = 2*A005993(n-1).
The flattened triangle is simply 2 followed by A137508.
If A106314 is interpreted as a triangle, T(n,m) = 2*A106314(n,m).
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10011 (First 141 rows).
EXAMPLE
The table starts in row n=1 with columns 1<=m<=n as:
2;
2,2;
2,8,2;
2,8,8,2;
2,8,18,8,2;
2,8,18,18,8,2;
...
MAPLE
A168281 := proc(n, m) 2*(min(n+1-m, m))^2 ; end proc:
seq(seq(A168281(n, m), m=1..n), n=1..20) ;
MATHEMATICA
Table[Map[2 Min[n + # - 1, #]^2 &, Drop[#, -Boole@ EvenQ@ n] ~Join~ Reverse@ # &@ Range@ Floor[n/2]], {n, 2, 14}] // Flatten (* Michael De Vlieger, Jul 19 2016 *)
CROSSREFS
KEYWORD
nonn,tabl,easy
AUTHOR
Paul Curtz, Nov 22 2009
EXTENSIONS
Rephrased all comments in terms of a triangle by R. J. Mathar, Nov 24 2010
More terms from Michael De Vlieger, Jul 19 2016
Definition corrected by Georg Fischer, Nov 11 2021
STATUS
approved