A362463 Array of numbers read by upward antidiagonals: leading row lists the primes as they were in the 19th century (A008578); the following rows give absolute values of differences of previous row.
1, 1, 2, 0, 1, 3, 1, 1, 2, 5, 0, 1, 0, 2, 7, 1, 1, 2, 2, 4, 11, 0, 1, 2, 0, 2, 2, 13, 1, 1, 2, 0, 0, 2, 4, 17, 0, 1, 2, 0, 0, 0, 2, 2, 19, 1, 1, 2, 0, 0, 0, 0, 2, 4, 23, 0, 1, 2, 0, 0, 0, 0, 0, 2, 6, 29, 1, 1, 0, 2, 2, 2, 2, 2, 2, 4, 2, 31, 0, 1, 0, 0, 2, 0, 2, 0, 2, 0, 4, 6, 37, 1, 1, 0, 0, 0, 2, 2, 0, 0, 2, 2, 2, 4, 41
Offset: 1
Examples
The array begins: 1 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 1 1 2 2 4 2 4 2 4 6 2 6 4 2 4 6 6 2 6 4 0 1 0 2 2 2 2 2 2 4 4 2 2 2 2 0 4 4 2 2 1 1 2 0 0 0 0 0 2 0 2 0 0 0 2 4 0 2 0 2 0 1 2 0 0 0 0 2 2 2 2 0 0 2 2 4 2 2 2 0 1 1 2 0 0 0 2 0 0 0 2 0 2 0 2 2 0 0 2 2 0 1 2 0 0 2 2 0 0 2 2 2 2 2 0 2 0 2 0 0 1 1 2 0 2 0 2 0 2 0 0 0 0 2 2 2 2 2 0 0 0 1 2 2 2 2 2 2 2 0 0 0 2 0 0 0 0 2 0 0 1 1 0 0 0 0 0 0 2 0 0 2 2 0 0 0 2 2 0 0 The first few antidiagonals are: 1, 1, 2, 0, 1, 3, 1, 1, 2, 5, 0, 1, 0, 2, 7, 1, 1, 2, 2, 4, 11, 0, 1, 2, 0, 2, 2, 13, 1, 1, 2, 0, 0, 2, 4, 17, 0, 1, 2, 0, 0, 0, 2, 2, 19, 1, 1, 2, 0, 0, 0, 0, 2, 4, 23, 0, 1, 2, 0, 0, 0, 0, 0, 2, 6, 29,
Links
- Paolo Xausa, Table of n, a(n) for n = 1..11325 (antidiagonals 1..150 of the array, flattened)
- N. J. A. Sloane, New Gilbreath Conjectures, Sum and Erase, Dissecting Polygons, and Other New Sequences, Doron Zeilberger's Exper. Math. Seminar, Rutgers, Sep 14 2023: Video, Slides, Updates. (Mentions this sequence.)
Programs
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Mathematica
A362463[dmax_]:=With[{d=Reverse[NestList[Abs[Differences[#]]&,Join[{1},Prime[Range[dmax-1]]],dmax-1]]},Array[Diagonal[d,#]&,dmax,1-dmax]];A362463[20] (* Generates 20 antidiagonals *) (* Paolo Xausa, May 08 2023 *)
Comments