The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A329956 Expansion of q^(-1/3) * eta(q)^3 * eta(q^3) * eta(q^6) / eta(q^2)^2 in powers of q. 1
1, -3, 2, -2, 8, -7, 2, -4, 7, -10, 2, -2, 16, -10, 6, -4, 7, -16, 4, -6, 16, -15, 6, -4, 12, -10, 6, -6, 24, -20, 4, -4, 12, -21, 6, -6, 24, -26, 4, -8, 13, -10, 10, -8, 32, -10, 6, -12, 12, -32, 6, -4, 32, -26, 10, -4, 13, -30, 10, -10, 24, -20, 8, -8, 24 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
Euler transform of period 6 sequence [-3, -1, -4, -1, -3, -3, ...].
G.f.: Product_{k>=1} (1 - x^(2*k)) * (1 - x^(3*k)) * (1 - x^(6*k)) / (1 - x^k)^3.
A329955(3*n + 1) = -a(n).
EXAMPLE
G.f. = 1 - 3*x + 2*x^2 - 2*x^3 + 8*x^4 - 7*x^5 + 2*x^6 - 4*x^7 + ...
G.f. = q - 3*q^4 + 2*q^7 - 2*q^10 + 8*q^13 - 7*q^16 + 2*q^19 - 4*q^22 + ...
MATHEMATICA
a[ n_] := SeriesCoefficient[ QPochhammer[ x]^3 QPochhammer[ x^3] QPochhammer[ x^6] / QPochhammer[ x^2]^2, {x, 0, n}];
PROG
(PARI) {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x + A)^3 * eta(x^3 + A) * eta(x^6 + A) / eta(x^2 + A)^2, n))};
CROSSREFS
Cf. A329955.
Sequence in context: A266275 A288536 A268864 * A242703 A141456 A137445
KEYWORD
sign
AUTHOR
Michael Somos, Nov 29 2019
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 4 13:10 EDT 2024. Contains 373098 sequences. (Running on oeis4.)