OFFSET
0,17
COMMENTS
a(n) is maximal element of row n of triangle A219180 or 0 if the row is empty. a(n) = 0 iff n in {1,4,6}.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..3500
FORMULA
a(n) = max_{k>=0} A219180(n,k).
EXAMPLE
a(31) = 4 because there are 4 partitions of 31 into 3 distinct prime parts ([3,5,23], [3,11,17], [5,7,19], [7,11,13]) but not more than 4 partitions of 31 into k distinct prime parts for any other k.
MAPLE
with(numtheory):
b:= proc(n, i) option remember;
`if`(n=0, [1], `if`(i<1, [0], zip((x, y)->x+y, b(n, i-1),
[0, `if`(ithprime(i)>n, [], b(n-ithprime(i), i-1))[]], 0)))
end:
a:= n-> max(b(n, pi(n))[]):
seq(a(n), n=0..120);
MATHEMATICA
zip = With[{m = Max[Length[#1], Length[#2]]}, PadRight[#1, m] + PadRight[#2, m]]&; b[n_, i_] := b[n, i] = If[n == 0, {1}, If[i<1, {0}, zip[b[n, i-1], Join[{0}, If[Prime[i]>n, {}, b[n-Prime[i], i-1]]]]]]; a[n_] := Max[b[n, PrimePi[n]]]; Table[a[n], {n, 0, 120}] (* Jean-François Alcover, Feb 12 2017, translated from Maple *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 13 2012
STATUS
approved