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A059776 Three-quadrant Ferrers graphs that partition n. 3
1, 2, 5, 11, 24, 48, 95, 178, 328, 585, 1025, 1754, 2958, 4897, 8002, 12889, 20523, 32289, 50296, 77550, 118521, 179553, 269881, 402532, 596178, 876942, 1281777, 1862015, 2689405, 3862891, 5519403, 7846393, 11100970, 15632733, 21917280 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

G. E. Andrews, Three-quadrant Ferrers graphs, Indian J. Math., 42 (No. 1, 2000), 1-7.

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..10000

FORMULA

a(n) ~ exp(Pi*sqrt(2*n)) / (2^(11/2) * n^(3/2)). - Vaclav Kotesovec, Jul 12 2018

MAPLE

t1 := add( (-1)^(j)*q^(j*(j+1)/2)*(1-q^(j+1))/(1-q), j=0..101); t3 := mul((1-q^n)^3, n=1..101); series(t1/t3, q, 101);

MATHEMATICA

nmax = 50; CoefficientList[Series[Sum[(-1)^k*x^(k*(k+1)/2)*(1 - x^(k + 1))/(1 - x), {k, 0, nmax}]/Product[(1 - x^k)^3, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 11 2018 *)

CROSSREFS

Cf. A000041, A001522, A059777.

Sequence in context: A208952 A091358 A091359 * A091360 A300277 A294378

Adjacent sequences:  A059773 A059774 A059775 * A059777 A059778 A059779

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Feb 21 2001

STATUS

approved

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Last modified May 22 05:51 EDT 2022. Contains 353933 sequences. (Running on oeis4.)