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A028283
Central elements in 4-Pascal triangle A028275 (by row).
2
1, 4, 10, 32, 110, 392, 1428, 5280, 19734, 74360, 281996, 1074944, 4115020, 15808912, 60917800, 235350720, 911315430, 3535767000, 13742347740, 53495534400, 208537056420, 813950932080, 3180614712600, 12441628655040
OFFSET
0,2
COMMENTS
Equals A000984, [1, 2, 6, 20, 70, ...] convolved with [1, 2, 0, 0, 0, ...]. - Gary W. Adamson, Jun 05 2009
FORMULA
a(n) = 2*A051960(n-1).
a(n) = 2*A000108(n)*(3n-1). - Ralf Stephan, Aug 24 2003
CROSSREFS
KEYWORD
nonn,easy
STATUS
approved