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A119646
a(n) = maximum number of partitions of n into 3 parts, each having the same product.
1
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 3, 3, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3
OFFSET
3,11
EXAMPLE
a(3)=1, because there is only one way to partition 3.
a(13)=2, because 13 = 6+6+1 = 9+2+2 and 6*6*1 = 9*2*2 = 36.
a(39)=3, because 39 = 20+15+4 = 24+10+5 = 25+8+6 and 20*15*4 = 24*10*5 = 25*8*6 = 1200.
See A103277 for more examples.
MATHEMATICA
pdt[lst_] := lst[[1]]*lst[[2]]*lst[[3]];
tanya[n_] := Max[Length /@ Split[Sort[pdt /@ Union[ Partition[Last /@ Flatten[ FindInstance[a + b + c == n && a >= b >= c > 0, {a, b, c}, Integers, (* failsafe *) Round[n^2/12]]], 3]] ]]];
Table[ tanya@n, {n, 4, 108}]
Table[SortBy[Tally[Times@@@IntegerPartitions[n, {3}]], Last][[-1, 2]], {n, 3, 110}] (* Harvey P. Dale, Jan 08 2023 *)
CROSSREFS
Sequence in context: A230866 A158209 A234538 * A024693 A025126 A129706
KEYWORD
nonn
AUTHOR
Joseph Biberstine (jrbibers(AT)indiana.edu) and Robert G. Wilson v, Jul 27 2006
EXTENSIONS
Name clarified by Dmitry Kamenetsky, Aug 02 2015
STATUS
approved