login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A231429 Number of partitions of 2n into distinct parts < n. 2
1, 0, 0, 0, 0, 1, 2, 4, 8, 14, 22, 35, 53, 78, 113, 160, 222, 306, 416, 558, 743, 980, 1281, 1665, 2149, 2755, 3514, 4458, 5626, 7070, 8846, 11020, 13680, 16920, 20852, 25618, 31375, 38309, 46649, 56651, 68616, 82908, 99940, 120192, 144238, 172730, 206425 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

LINKS

Table of n, a(n) for n=0..46.

EXAMPLE

a(5) = #{4+3+2+1} = 1;

a(6) = #{5+4+3, 5+4+2+1} = 2;

a(7) = #{6+5+3, 6+5+2+1, 6+4+3+1, 5+4+3+2} = 4;

a(8) = #{7+6+3, 7+6+2+1, 7+6+3, 7+5+3+1, 7+4+3+2, 6+5+4+1, 6+5+3+2, 6+4+3+2+1} = 8;

a(9) = #{8+7+3, 8+7+2+1, 8+6+4, 8+6+3+1, 8+5+4+1, 8+5+3+2, 8+4+3+2+1, 7+6+5, 7+6+4+1, 7+6+3+2, 7+5+4+2, 7+5+3+2+1, 6+5+4+3, 6+5+4+2+1} = 14.

PROG

(Haskell)

a231429 n = p [1..n-1] (2*n) where

   p _  0 = 1

   p [] _ = 0

   p (k:ks) m = if m < k then 0 else p ks (m - k) + p ks m

CROSSREFS

Cf. A209815, A079122.

Sequence in context: A087151 A053798 A305497 * A259392 A261968 A138526

Adjacent sequences:  A231426 A231427 A231428 * A231430 A231431 A231432

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Nov 14 2013

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 16 11:54 EDT 2021. Contains 343942 sequences. (Running on oeis4.)