OFFSET
0,7
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
EXAMPLE
a(10) counts these 8 partitions: 7111, 55, 4411, 4222, 421111, 3331, 3322, 322111.
MAPLE
b:= proc(n, i, t) option remember; `if`(n=0, `if`(t=0, 1, 0),
`if`(i<1, 0, add(b(n-i*j, i-1, t+`if`(j>0, 2, 0)-j), j=0..n/i)))
end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..60);
MATHEMATICA
z = 55; d[p_] := d[p] = Length[DeleteDuplicates[p]]; Table[Count[IntegerPartitions[n], p_ /; 2*d[p] == Length[p]], {n, 0, z}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Mar 30 2014
STATUS
approved