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A081622 Number of 6-core partitions of n. +0
2
1, 1, 2, 3, 5, 7, 5, 9, 10, 12, 12, 14, 20, 20, 21, 23, 24, 24, 32, 29, 35, 36, 44, 47, 38, 47, 49, 52, 55, 58, 59, 64, 66, 71, 70, 78, 79, 88, 87, 90, 85, 87, 111, 104, 102, 107, 112, 113, 121, 113, 130, 130, 148, 153, 132, 147, 149, 156, 162, 149, 167, 160, 178, 180 (list; graph; listen)
OFFSET

0,3

COMMENT

Euler transform of period 6 sequence [1,1,1,1,1,-5,...].

Expansion of eta(q^6)^6/(eta(q)q^(35/24)) in powers of q.

REFERENCES

Garvan, F., Kim, D., and Stanton, D., Cranks and t-cores, Inventiones Math. 101 (1990) 1-17

LINKS

T. D. Noe, Table of n, a(n) for n=0..1000

FORMULA

G.f.: Product_{k>0} (1-q^(6k))^6/(1-q^k).

PROGRAM

(PARI) a(n)=if(n<0, 0, polcoeff(prod(k=1, n, (1-x^(6*k)+x*O(x^n))^6/(1-x^k)), n))

(PARI) {a(n)=local(A); if(n<0, 0, A=x*O(x^n); polcoeff(eta(x^6+A)^6/eta(x+A), n))}

CROSSREFS

Cf. A010054, A033687, A045831, A053723, A053724.

Sequence in context: A103866 A080164 A126048 this_sequence A064143 A115274 A126890

Adjacent sequences: A081619 A081620 A081621 this_sequence A081623 A081624 A081625

KEYWORD

nonn,easy

AUTHOR

Michael Somos, Mar 24, 2003

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Last modified July 26 23:19 EDT 2008. Contains 142293 sequences.


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