OFFSET
1,1
LINKS
FORMULA
A317241(A(n,k)) = k.
EXAMPLE
A(6,2) = 49: 1 + 3 * (1 + 5 * (1 + 2)) = 1 + 2 * (1 + 23) = 49.
Square array A(n,k) begins:
2, 1, 25, 43, 211, 638, 664, 1613, 2991, ...
5, 3, 29, 61, 261, 848, 1956, 3321, 3004, ...
7, 4, 37, 91, 421, 921, 2058, 3336, 3319, ...
11, 6, 40, 111, 426, 969, 2092, 3368, 3554, ...
15, 8, 41, 121, 441, 1002, 2094, 3741, 3928, ...
23, 9, 49, 124, 484, 1026, 2283, 3914, 4846, ...
26, 10, 51, 171, 535, 1106, 2381, 3979, 5552, ...
27, 12, 52, 184, 540, 1156, 2388, 4082, 5886, ...
28, 13, 67, 187, 591, 1191, 2432, 4126, 6293, ...
MAPLE
b:= proc(n, s) option remember; `if`(n=1, 1, add(b((n-1)/p,
s union {p}) , p=numtheory[factorset](n-1) minus s))
end:
A:= proc() local h, p, q; p, q:= proc() [] end, 0;
proc(n, k)
while nops(p(k))<n do q:= q+1;
h:= b(q, {});
p(h):= [p(h)[], q]
od; p(k)[n]
end
end():
seq(seq(A(n, d-n), n=1..d), d=1..10);
MATHEMATICA
b[n_, s_List] := b[n, s] = If[n == 1, 1, Sum[If[p == 1, 0, b[(n - 1)/p, s ~Union~ {p}]], {p, FactorInteger[n - 1][[All, 1]] ~Complement~ s}]];
A[n_, k_] := Module[{h, p, q = 0}, p[_] = {}; While[Length[p[k]] < n, q = q + 1; h = b[q, {}]; p[h] = Append[p[h], q]]; p[k][[n]]];
Table[Table[A[n, d - n], {n, 1, d}], {d, 1, 11}] // Flatten (* Jean-François Alcover, Dec 06 2019, from Maple *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Alois P. Heinz, Jul 27 2018
STATUS
approved