This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A239961 Number of partitions of n such that (number of distinct parts) = number of 2's. 2
 1, 0, 1, 0, 0, 1, 1, 2, 2, 2, 4, 4, 6, 9, 10, 12, 19, 21, 24, 36, 44, 49, 66, 81, 100, 123, 144, 180, 229, 265, 317, 391, 473, 566, 675, 798, 968, 1154, 1354, 1621, 1926, 2241, 2675, 3170, 3691, 4345, 5113, 5956, 7002, 8182, 9503, 11095, 12919, 14976, 17446 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..1000 EXAMPLE a(10) counts these 4 partitions :  622, 3322, 32221, 22111111. MAPLE b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,       b(n, i-1)+`if`(i=2, 0, add(b(n-2-i*j, i-1), j=1..(n-2)/i))))     end: a:= n-> `if`(n=0, 1, b(n-2\$2)): seq(a(n), n=0..70);  # Alois P. Heinz, Apr 03 2014 MATHEMATICA z = 54; d[p_] := d[p] = Length[DeleteDuplicates[p]]; Table[Count[IntegerPartitions[n], p_ /; d[p] == Count[p, 2]], {n, 0, z}] CROSSREFS Cf. A239960. Sequence in context: A173388 A097196 A132325 * A301588 A010238 A178799 Adjacent sequences:  A239958 A239959 A239960 * A239962 A239963 A239964 KEYWORD nonn,easy AUTHOR Clark Kimberling, Mar 30 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 21 22:19 EDT 2019. Contains 321382 sequences. (Running on oeis4.)