A002759 Number of bipartite partitions of n white objects and 10 black ones. (Formerly M5278 N2295)

42, 139, 392, 907, 1941, 3804, 7128, 12693, 21893, 36535, 59521, 94664, 147794, 226524, 342006, 508866, 747753, 1085635, 1559725, 2218272, 3126541, 4368724, 6056705, 8333955, 11388614, 15460291, 20859497, 27979454, 37324367, 49529018

Offset

0,1

Comments

Number of ways to factor p^n*q^10 where p and q are distinct primes.

a(n) is the number of multiset partitions of the multiset {r^n, s^10}. - Joerg Arndt, Jan 01 2024

References

M. S. Cheema and H. Gupta, Tables of Partitions of Gaussian Integers. National Institute of Sciences of India, Mathematical Tables, Vol. 1, New Delhi, 1956, p. 2.

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 (terms 0..200 from Alois P. Heinz)

M. S. Cheema and H. Gupta, Tables of Partitions of Gaussian Integers. National Institute of Sciences of India, Mathematical Tables, Vol. 1, New Delhi, 1956 (Annotated scanned pages from, plus a review)

Formula

a(n) = if n <= 10 then A054225(10,n) else A054225(n,10). - Reinhard Zumkeller, Nov 30 2011

a(n) ~ sqrt(3) * n^4 * exp(Pi*sqrt(2*n/3)) / (5600*Pi^10). - Vaclav Kotesovec, Feb 01 2016

Mathematica

p = 2; q = 3; b[n_, k_] := b[n, k] = If[n>k, 0, 1] + If[PrimeQ[n], 0, Sum[If[d>k, 0, b[n/d, d]], {d, DeleteCases[Divisors[n], 1|n]}]]; a[n_] := b[p^n*q^10, p^n*q^10]; Table[a[n], {n, 0, 29}] (* Jean-François Alcover, Mar 17 2014, after Alois P. Heinz *)
nmax = 50; CoefficientList[Series[(42 + 55*x + 72*x^2 + 68*x^3 + 55*x^4 + 22*x^5 - 21*x^6 - 72*x^7 - 126*x^8 - 178*x^9 - 222*x^10 - 203*x^11 - 169*x^12 - 81*x^13 + 15*x^14 + 125*x^15 + 209*x^16 + 286*x^17 + 303*x^18 + 299*x^19 + 219*x^20 + 107*x^21 - 4*x^22 - 117*x^23 - 208*x^24 - 263*x^25 - 257*x^26 - 232*x^27 - 151*x^28 - 69*x^29 + 29*x^30 + 92*x^31 + 130*x^32 + 145*x^33 + 143*x^34 + 97*x^35 + 48*x^36 - 2*x^37 - 39*x^38 - 48*x^39 - 58*x^40 - 41*x^41 - 31*x^42 - 19*x^43 - 4*x^44 + 19*x^45 + 21*x^46 + 20*x^47 + 13*x^48 - 4*x^49 - 9*x^50 - 10*x^51 + 2*x^52 + 4*x^53 - x^54)/((1-x) * (1-x^2) * (1-x^3) * (1-x^4) * (1-x^5) * (1-x^6) * (1-x^7) * (1-x^8) * (1-x^9) * (1-x^10)) * Product[1/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Feb 01 2016 *)

Crossrefs

Column 10 of A054225.

Cf. A005380.

Sequence in context: A244102 A045088 A303860 * A346856 A330939 A044374

Adjacent sequences: A002756 A002757 A002758 * A002760 A002761 A002762

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Edited by Christian G. Bower, Jan 08 2004

Status

approved