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A362464
Array of numbers read by upward antidiagonals: leading row lists sigma(i), i >= 1 (cf. A000203); the following rows give absolute values of differences of previous row.
2
1, 2, 3, 1, 1, 4, 1, 2, 3, 7, 1, 0, 2, 1, 6, 2, 3, 3, 5, 6, 12, 1, 3, 0, 3, 2, 4, 8, 0, 1, 2, 2, 1, 3, 7, 15, 0, 0, 1, 1, 1, 2, 5, 2, 13, 1, 1, 1, 0, 1, 0, 2, 3, 5, 18, 0, 1, 0, 1, 1, 0, 0, 2, 1, 6, 12, 4, 4, 5, 5, 6, 7, 7, 7, 9, 10, 16, 28, 0, 4, 0, 5, 0, 6, 1, 6, 1, 8, 2, 14, 14
OFFSET
1,2
COMMENTS
The leading entries in the rows form A362451, the Gilbreath transform of sigma.
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..11325 (antidiagonals 1..150 of the array, flattened)
EXAMPLE
The array begins:
1, 3, 4, 7, 6, 12, 8, 15, 13, 18, 12, 28, 14, 24, 24, 31, ...
2, 1, 3, 1, 6, 4, 7, 2, 5, 6, 16, 14, 10, 0, 7, ...
1, 2, 2, 5, 2, 3, 5, 3, 1, 10, 2, 4, 10, 7, ...
1, 0, 3, 3, 1, 2, 2, 2, 9, 8, 2, 6, 3, ...
1, 3, 0, 2, 1, 0, 0, 7, 1, 6, 4, 3, ...
2, 3, 2, 1, 1, 0, 7, 6, 5, 2, 1, ...
1, 1, 1, 0, 1, 7, 1, 1, 3, 1, ...
...
The first few antidiagonals are:
1
2, 3
1, 1, 4
1, 2, 3, 7
1, 0, 2, 1, 6
2, 3, 3, 5, 6, 12
1, 3, 0, 3, 2, 4, 8
0, 1, 2, 2, 1, 3, 7, 15
...
MAPLE
See link.
MATHEMATICA
A362464[dmax_]:=With[{d=Reverse[NestList[Abs[Differences[#]]&, DivisorSigma[1, Range[dmax]], dmax-1]]}, Array[Diagonal[d, #]&, dmax, 1-dmax]]; A362464[20] (* Generates 20 antidiagonals *) (* Paolo Xausa, May 10 2023 *)
CROSSREFS
Sequence in context: A139343 A059247 A340940 * A244665 A194518 A023572
KEYWORD
nonn,look,tabl
AUTHOR
N. J. A. Sloane, May 09 2023
STATUS
approved