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A319080
Sequence, read by rows, encoding an infinite sequence of diamond-shaped arrays of nonnegative integers (see example).
0
0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 2, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 3, 2, 1, 0, 0, 1, 2, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 3, 2, 1, 0, 0, 1, 2, 3, 4, 3, 2, 1, 0, 0, 1, 2, 3, 2, 1, 0, 0, 1, 2, 1, 0, 0, 1, 0, 0
OFFSET
0,13
COMMENTS
The sum of each figure corresponds to A005900;
Figure 1:
0 = 0;
Figure 2:
0+0+1+0+0 = 1;
Figure 3:
0+0+1+0+0+1+2+1+0+0+1+0+0 = 6;
Figure n:
0+0+1+0+0+1+2+1+0+...+n+...0+1+2+1+0+0+1+0+0 = A005900(n).
EXAMPLE
Figure 1 has just 0. Figure 2 would look like a 1 surrounded by 0's. Figure 3 would look like a 2 surrounded by 1's surrounded by 0's, etc.
Read by rows, the sequence starts:
Figure 1: 0;
0
Figure 2: 0, 0, 1, 0, 0;
0
0 1 0
0
Figure 3: 0, 0, 1, 0, 0, 1, 2, 1, 0, 0, 1, 0, 0;
0
0 1 0
0 1 2 1 0
0 1 0
0
Figure 4: 0, 0, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 3, 2, 1, 0, 0, 1, 2, 1, 0, 0, 1, 0, 0;
0
0 1 0
0 1 2 1 0
0 1 2 3 2 1 0
0 1 2 1 0
0 1 0
0
...
MATHEMATICA
f[n_] := Join[#, Rest@ Reverse@ #] &@ Range[0, n]; Array[Flatten[f /@ f@ #] &, 5, 0] // Flatten (* Michael De Vlieger, Sep 10 2018 *)
CROSSREFS
Sequence in context: A115079 A286562 A185644 * A025435 A304685 A186714
KEYWORD
nonn,tabf
AUTHOR
Kritsada Moomuang, Sep 09 2018
STATUS
approved