login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A001452 Number of 5-line partitions of n.
(Formerly M2564 N1015)
11
1, 1, 3, 6, 13, 24, 47, 83, 152, 263, 457, 768, 1292, 2118, 3462, 5564, 8888, 14016, 21973, 34081, 52552, 80331, 122078, 184161, 276303, 411870, 610818, 900721, 1321848, 1929981, 2805338, 4058812, 5847966, 8390097, 11990531, 17069145, 24210571, 34215537, 48190451, 67644522 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Planar partitions into at most five rows. [Joerg Arndt, May 01 2013]

Number of partitions of n where there are k sorts of parts k for k<=4 and 5 sorts all other parts. [Joerg Arndt, Mar 15 2014]

REFERENCES

P. A. MacMahon, The connexion between the sum of the squares of the divisors and the number of partitions of a given number, Messenger Math., 54 (1924), 113-116.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Alois P. Heinz and Vaclav Kotesovec, Table of n, a(n) for n = 0..10000 (first 1000 terms from Alois P. Heinz)

M. S. Cheema and B. Gordon, Some remarks on two- and three-line partitions, Duke Math. J., 31 (1964), 267-273.

Vaclav Kotesovec, Graph - The asymptotic ratio (50000 terms)

FORMULA

G.f.: 1 / prod(k>=1, (1-x^k)^min(k,5) ). - Sean A. Irvine, Jul 24 2012

a(n) ~ 15625 * Pi^10 * sqrt(5) * exp(Pi*sqrt(10*n/3)) / (2592 * sqrt(3) * n^7). - Vaclav Kotesovec, Oct 28 2015

MAPLE

with(numtheory):

a:= proc(n) option remember; `if`(n=0, 1, add(add(

      min(d, 5)*d, d=divisors(j))*a(n-j), j=1..n)/n)

    end:

seq(a(n), n=0..45);  # Alois P. Heinz, Mar 15 2014

MATHEMATICA

a[n_] := a[n] = If[n == 0, 1, Sum[Sum[Min[d, 5]*d, {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 45}] (* Jean-Fran├žois Alcover, Mar 17 2014, after Alois P. Heinz *)

nmax = 40; CoefficientList[Series[(1-x)^4 * (1-x^2)^3 * (1-x^3)^2 * (1-x^4) * Product[1/(1-x^k)^5, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Oct 28 2015 *)

PROG

(PARI) x='x+O('x^66); r=5; Vec( prod(k=1, r-1, (1-x^k)^(r-k)) / eta(x)^r ) \\ Joerg Arndt, May 01 2013

CROSSREFS

A row of the array in A242641.

Sequences "number of r-line partitions": A000041 (r=1), A000990 (r=2), A000991 (r=3), A002799 (r=4), A001452 (r=5), A225196 (r=6), A225197 (r=7), A225198 (r=8), A225199 (r=9).

Sequence in context: A293076 A293421 A018081 * A005405 A225196 A225197

Adjacent sequences:  A001449 A001450 A001451 * A001453 A001454 A001455

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Sean A. Irvine, Jul 24 2012

Prepended a(0)=1, Joerg Arndt, May 01 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 20 07:15 EST 2018. Contains 299359 sequences. (Running on oeis4.)