[seqfan] Pseudotriangle

Paul Curtz bpcrtz at free.fr
Mon Jun 1 14:14:56 CEST 2020


Hello,
                                   sum
   0                                0
   0                                0
   0  1                             1
   0  2  2                          4
   0  3  4                          7
   0  4  6  3                      13
   0  5  8  6  4                   23
   0  6 10  9  8                   33
   0  7 12 12 12  5                48
   0  8 14 15 16 10  6             69
   0  9 16 18 20 15 12             90
   ...
  b(n) = 0, 0, A038391(n).

b(n) first two differences:
  0,  0,  1,  4,  7, 13, 23, 33, 48, 69, 90, 118, 154, ...
  0,  1,  3,  3,  6, 10, 10, 15, 21, 21, 28,  36,  36, ... (from A000217(n))
  1,  2,  0,  3,  4,  0,  5,  6,  0,  7,  8,   0,   9, ... = A117909(n).

Is this kind of partial triangle known?

Best regards

Paul


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