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A219209
Maximal product of all parts of a partition of n into distinct divisors of n.
2
1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 48, 13, 14, 15, 16, 17, 162, 19, 200, 21, 22, 23, 1152, 25, 26, 27, 784, 29, 1350, 31, 32, 33, 34, 35, 15552, 37, 38, 39, 6400, 41, 2058, 43, 44, 45, 46, 47, 73728, 49, 50, 51, 52, 53, 8748, 55, 25088, 57, 58, 59, 864000
OFFSET
0,3
LINKS
EXAMPLE
a(0) = 1: the empty product.
a(p) = p for any prime p: [p]-> p.
a(12) = 48: [2,4,6]-> 48.
a(20) = 200: [1,4,5,10]-> 200.
a(24) = 1152: [1,2,3,4,6,8]-> 1152.
MAPLE
a:= proc(n) local b, l;
l:= sort([numtheory[divisors](n)[]]);
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
max(b(n, i-1), `if`(l[i]>n, 0, l[i] *b(n-l[i], i-1)))))
end; forget(b);
b(n, nops(l))
end:
seq(a(n), n=0..80);
MATHEMATICA
a[n_] := a[n] = Module[{b, l}, l = Divisors[n]; b[m_, i_] := b[m, i] = If[m == 0, 1, If[i<1, 0, Max[b[m, i-1], If[l[[i]]>m, 0, l[[i]]*b[m-l[[i]], i-1] ]]]]; b[n, Length[l]]]; Table[a[n], {n, 0, 80}] (* Jean-François Alcover, Feb 16 2017, translated from Maple *)
CROSSREFS
The number of distinct products are in A219208.
Sequence in context: A004851 A066638 A285769 * A223474 A062279 A088599
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 14 2012
STATUS
approved