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A140408
Irregular triangle T(n,k) read by rows: n repetitions of -1 followed by (n+1) repetitions of n+1.
0
1, -1, 2, 2, -1, -1, 3, 3, 3, -1, -1, -1, 4, 4, 4, 4, -1, -1, -1, -1, 5, 5, 5, 5, 5, -1, -1, -1, -1, -1, 6, 6, 6, 6, 6, 6, -1, -1, -1, -1, -1, -1, 7, 7, 7, 7, 7, 7, 7, -1, -1, -1, -1, -1, -1, -1, 8, 8, 8, 8, 8, 8, 8, 8, -1, -1, -1, -1, -1, -1, -1, -1, 9, 9, 9, 9, 9, 9, 9, 9, 9, -1, -1, -1, -1, -1, -1, -1, -1, -1, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10
OFFSET
0,3
COMMENTS
Row n has 2n+1 terms.
EXAMPLE
1,
-1, 2, 2,
-1, -1, 3, 3, 3,
-1, -1, -1, 4, 4, 4, 4,
-1, -1, -1, -1, 5, 5, 5, 5, 5,
-1, -1, -1, -1, -1, 6, 6, 6, 6, 6, 6,
-1, -1, -1, -1, -1, -1, 7, 7, 7, 7, 7, 7, 7,
-1, -1, -1, -1, -1, -1, -1, 8, 8, 8, 8, 8, 8, 8, 8,
-1, -1, -1, -1, -1, -1, -1, -1, 9, 9, 9, 9, 9, 9, 9, 9, 9,
-1, -1, -1, -1, -1, -1, -1, -1, -1, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10
MATHEMATICA
Flatten[Table[Join[PadRight[{}, n, -1], PadRight[{}, n+1, n+1]], {n, 0, 9}]] (* Harvey P. Dale, May 07 2014 *)
CROSSREFS
Cf. A002061 (row sums).
Sequence in context: A308068 A100522 A258140 * A047080 A036064 A352744
KEYWORD
sign,tabf,easy
AUTHOR
Paul Curtz, Jun 16 2008
STATUS
approved