OFFSET
0,31
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = A025155(n-9), n>9. - R. J. Mathar, Jul 31 2008
G.f.: x^9*Product_{j>=10} (1+x^j). - R. J. Mathar, Jul 31 2008
G.f.: Sum_{k>=1} x^(k*(k + 17)/2) / Product_{j=1..k-1} (1 - x^j). - Ilya Gutkovskiy, Nov 25 2020
MAPLE
b:= proc(n, i) option remember;
`if`(n=0, 1, `if`((i-9)*(i+10)/2<n, 0,
add(b(n-i*j, i-1), j=0..min(1, n/i))))
end:
a:= n-> `if`(n<9, 0, b(n-9$2)):
seq(a(n), n=0..100); # Alois P. Heinz, Feb 07 2014
MATHEMATICA
dp9[n_]:=Module[{ips=IntegerPartitions[n]}, Length[Select[ips, Min[#] == 9 && Length[#]==Length[Union[#]]&]]]; Table[dp9[n], {n, 0, 80}] (* Harvey P. Dale, Oct 23 2015 *)
Join[{0}, Table[Count[Last /@ Select[IntegerPartitions@n, DeleteDuplicates[#] == # &], 9], {n, 66}]] (* Robert Price, Jun 13 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved