cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A238480 Number of partitions p of n that include (min(p) + max(p))/2 as a part.

Original entry on oeis.org

1, 2, 2, 3, 2, 5, 3, 6, 8, 9, 10, 20, 18, 25, 38, 43, 53, 77, 87, 114, 150, 176, 220, 290, 343, 422, 535, 641, 783, 978, 1164, 1415, 1733, 2068, 2497, 3026, 3595, 4304, 5174, 6140, 7300, 8709, 10283, 12176, 14435, 16978, 20001, 23579, 27640, 32423, 38024
Offset: 1

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Author

Clark Kimberling, Feb 27 2014

Keywords

Comments

A238480(n) + A238481(n) = A000041(n).

Examples

			a(6) counts these partitions:
  6 (as (6+6)/2 = 6 is included),
  33 (as (3+3)/2 = 3 is included),
  321 (as (3+1)/2 = 2 is included),
  222 (as (2+2)/2 = 2 is included),
  111111 (as (1+1)/2 = 1 is included).
Thus a(6) = 5.
		

Crossrefs

Cf. A238481.

Programs

  • Mathematica
    Table[Count[IntegerPartitions[n], p_ /; MemberQ[p, (Min[p] + Max[p])/2]], {n, 40}]