OFFSET
1,3
COMMENTS
The sorting in the Mathematica program is lexicographic.
FORMULA
See program.
EXAMPLE
M={{1}} where the last entry is {1}.
A={{1}} where the last entry {1} in M is found at position 1 in the ordered set of tuples A, therefore a(1)=1.
M={{1}, {2, -1}} where the last entry is {2,-1}.
A={{2, -1}, {2, 0}, {2, 1}} where the last entry {2,-1} in M is found at position 1 in the ordered set of tuples A, therefore a(2)=1.
M={{1}, {2, -1}, {3, 0, -2}} where the last entry is {3, 0, -2}.
A={{3, -1, -2}, {3, -1, -1}, {3, 0, -2}, {3, -1, 0}, {3, 0, -1}, {3, 1, -2}, {3, -1, 1}, {3, 0, 0}, {3, 1, -1}, {3, -1, 2}, {3, 0, 1}, {3, 1, 0}, {3, 0, 2}, {3, 1, 1}, {3, 1, 2}} where the last entry {3, 0, -2} in M is found at position 3 in the ordered set of tuples A, therefore a(3)=3.
MATHEMATICA
Monitor[Flatten[Table[
nnn = nnnn;
g1 = Table[
T = Tuples[
Table[Table[If[k == 1, nn, n], {n, -(k - 1), k - 1}], {k, 1,
nn}]];
b = Sort[
Table[{T[[n]], Total[T[[n]]/Range[Length[T[[n]]]]] - nn}, {n,
1, Length[T]}], #1[[2]] < #2[[2]] &], {nn, 1, nnn}];
A = Table[b[[n]][[1]], {n, 1, Length[b]}];
Clear[T, n, k, b, a];
nn = nnn;
a[n_] := If[n < 1, 0, Sum[d MoebiusMu@d, {d, Divisors[n]}]];
M = Table[
Table[Sum[If[n >= k, a[GCD[n, k]], 0], {n, 1, m}], {k, 1,
m}], {m, 1, nn}];
Flatten[Position[A, M[[nnn]]]], {nnnn, 1, 8}]], nnnn]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Mats Granvik, Feb 23 2020
STATUS
approved