

A027337


Number of partitions of n that do not contain 3 as a part.


5



1, 1, 2, 2, 4, 5, 8, 10, 15, 19, 27, 34, 47, 59, 79, 99, 130, 162, 209, 259, 330, 407, 512, 628, 783, 956, 1181, 1435, 1760, 2129, 2594, 3124, 3784, 4539, 5468, 6534, 7834, 9327, 11132, 13208, 15701, 18568, 21989, 25923, 30592, 35960, 42297, 49579, 58139, 67967
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OFFSET

0,3


COMMENTS

a(n) is also the number of partitions of n with less than three 1's.  Geoffrey Critzer, Jun 20 2014


LINKS

Table of n, a(n) for n=0..49.


FORMULA

G.f.: (1x^3) Product_{m>0} 1/(1x^m).
a(n) = A000041(n)  A000041(n3).
a(n) ~ Pi * exp(sqrt(2*n/3)*Pi) / (4*sqrt(2)*n^(3/2)) * (1  (3*sqrt(3/2)/Pi + Pi/(24*sqrt(6)) + 3*Pi/(2*sqrt(6)))/sqrt(n) + (37/8 + 9/(2*Pi^2) + 1801*Pi^2/6912)/n).  Vaclav Kotesovec, Nov 04 2016


MATHEMATICA

nn=49; CoefficientList[Series[(1x^3)Product[1/(1x^i), {i, 1, nn}], {x, 0, nn}], x] (* Geoffrey Critzer, Jun 20 2014 *)


PROG

(PARI) a(n)=if(n<0, 0, polcoeff((1x^3)/eta(x+x*O(x^n)), n))


CROSSREFS

Cf. A000041, A027336, A027338.
Column k=0 of A263232.
Column 3 of A175788.
Sequence in context: A035991 A036002 A104504 * A325434 A326631 A260894
Adjacent sequences: A027334 A027335 A027336 * A027338 A027339 A027340


KEYWORD

nonn


AUTHOR

Clark Kimberling


STATUS

approved



